# Prometheus changelog

> The monitoring system and time-series database.

- Vendor: Prometheus
- Category: Infrastructure & DevOps
- License: Apache-2.0
- Language: Go
- Official site: https://prometheus.io
- Tracked by: What's New (https://whatsnew.fyi/product/prometheus)
- Harvested from: GitHub (prometheus/prometheus)
- Entries below: 17 (newest first)

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

## Releases

### v3.13.4 — 3.13.4 / 2026-09-29

- Date: 2026-10-02
- Version: v3.13.4
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.4
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.4

- **security** — Bump google.golang.org/grpc to v1.83.1 to fix HTTP/2 DATA frame fragmentation memory exhaustion (GO-2026-6348)
- **security** — Update vulnerable npm dependencies in UI
- **fixed** — Agent: Ignore unknown WAL record types to allow rolling back from newer versions
- **fixed** — Federation: Fix corruption of float native histograms
- **fixed** — Scrape: Fix failing scrapes of protobuf float histograms with zero sample, zero and bucket counts, such as the result of recording rate(x[1m]) over a constant histogram

- [SECURITY] Bump google.golang.org/grpc to v1.83.1 to fix HTTP/2 DATA frame fragmentation memory exhaustion (GO-2026-6348). #19834
- [SECURITY] UI: Update vulnerable npm dependencies. #19834
- [BUGFIX] Agent: Ignore unknown WAL record types to allow rolling back from newer versions. #19814
- [BUGFIX] Federation: Fix corruption of float native histograms. #19679
- [BUGFIX] Scrape: Fix failing scrapes of protobuf float histograms with zero sample, zero and bucket counts, such as the result of recording `rate(x[1m])` over a constant histogram. #19682

### v3.15.0 — 3.15.0 / 2026-09-24

- Date: 2026-09-25
- Version: v3.15.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.15.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.15.0

- **changed** — PromQL: Fix range query whose end was not aligned to step causing subqueries to evaluate past the parent's last actual step, inflating peakSamples and wasting storage I/O
- **changed** — PromQL: Do not register a start timestamp reset if the start timestamp hasn't changed between subsequent samples
- **deprecated** — Logging: Deprecate --log.level; use runtime.log_level configuration to supply the default level
- **added** — Configuration: Allow changing the process log level through runtime.log_level on configuration reload
- **added** — Prometheus: Add --auto-gomemlimit.refresh-interval flag to periodically re-detect the container or system memory limit and update GOMEMLIMIT at runtime
- **added** — Scraping: Add support for scraping targets via Unix Domain Sockets
- **added** — Scrape: Implement OM2.0 scrape format
- **changed** — Reduce TSDB head CPU utilization when initializing
- **changed** — Docker SD: Add labels __meta_docker_container_image and __meta_docker_container_image_id
- **changed** — Mixin: Add p95/p99 remote-write send-batch latency panel to the remote-write dashboard
- **changed** — PromQL/TSDB: The --enable-feature=st-storage flag now automatically enables XOR2 float chunk encoding and ST-capable histogram chunk encoding
- **changed** — Remote write / Alertmanager: Upgrade sigv4 to v0.5.0, adding session_name and tags fields for STS AssumeRole sessions
- **added** — Scraping: Support zstd-compressed scrape responses, enabled via feature flag zstd-scrape
- **changed** — TSDB: Stabilize the XOR2 float chunk encoding; --enable-feature=xor2-encoding is deprecated in favor of storage.tsdb.chunk_encoding.floats: xor2
- **added** — TSDB: Add prometheus_tsdb_head_appenders_created_total metric
- **changed** — Tracing: Add more spans to scrapes, API queries and rule evaluations
- **changed** — UI: Show the effective configuration for each scrape pool on the Targets and Service Discovery pages
- **changed** — Scrape: Enable start time synthesis for summary _count and _sum series in scrape appender v2
- **fixed** — PromQL: Fix info() enrichment for composite expressions with mixed @/offset references or selector-free vector branches
- **fixed** — PromQL: Fix info() enrichment when input series use different subsets of identifying labels

- [CHANGE] PromQL: A range query whose `end` was not aligned to `step` caused subqueries inside it to evaluate past the parent's last actual step, inflating `peakSamples` in the query stats and against the `query.max-samples` limit, and wasting storage I/O reading samples that were never used in the result. Add tests to prevent regression of the fix made in #18081. #18598
- [CHANGE] PromQL: Do not register a start timestamp reset if the start timestamp hasn't changed between subsequent samples. #19454
- [CHANGE] Logging: Deprecate `--log.level`; use `runtime.log_level` configuration to supply the default level. #19511
- [FEATURE] Configuration: Allow changing the process log level through `runtime.log_level` on configuration reload. #19511
- [FEATURE] Prometheus: Add `--auto-gomemlimit.refresh-interval` flag to periodically re-detect the container or system memory limit and update `GOMEMLIMIT` at runtime. #18843
- [FEATURE] Scraping: Add support for scraping targets via Unix Domain Sockets. #12024. #18091
- [FEATURE] scrape: Implement OM2.0 scrape format. #18606
- [ENHANCEMENT] Reduce TSDB head CPU utilization when initializing. #18001
- [ENHANCEMENT] Docker SD: Add labels `__meta_docker_container_image` and `__meta_docker_container_image_id`. #19386
- [ENHANCEMENT] Mixin: Add a p95/p99 remote-write send-batch latency panel to the remote-write dashboard. #19500
- [ENHANCEMENT] Mixin: Support native histograms in the remote-write send-batch latency panel. #19522
- [ENHANCEMENT] PromQL/TSDB: The `--enable-feature=st-storage` flag now automatically enables XOR2 float chunk encoding and ST-capable histogram chunk encoding, so you no longer need to pass `xor2-encoding` and `histograms-st-encoding` alongside it. #19518
- [ENHANCEMENT] Remote write / Alertmanager: upgrade sigv4 to v0.5.0, adding `session_name` and `tags` fields for STS AssumeRole sessions. The previously undocumented `service_name` field is now also documented. #19569
- [ENHANCEMENT] Scraping: Support zstd-compressed scrape responses, enabled via feature flag `zstd-scrape`. #19502
- [ENHANCEMENT] TSDB: Stabilize the XOR2 float chunk encoding. `--enable-feature=xor2-encoding` is deprecated; use `storage.tsdb.chunk_encoding.floats: xor2` instead. Check that other software reading the TSDB directly (e.g. Thanos sidecar) supports XOR2 before enabling. #19461
- [ENHANCEMENT] TSDB: add `prometheus_tsdb_head_appenders_created_total` metric. #19411
- [ENHANCEMENT] Tracing: add more spans to scrapes, API queries and rule evaluations. #19410
- [ENHANCEMENT] UI: Show the effective configuration for each scrape pool on the Targets and Service Discovery pages. #19384
- [ENHANCEMENT] scrape: Enable start time synthesis for summary `_count` and `_sum` series in scrape appender v2. #19323
- [ENHANCEMENT] scrape: stop all pools in parallel for faster shutdowns. #19295
- [ENHANCEMENT] storage/remote: Add undocumented failed_request_logging config field to debug log remote write V2 requests on send errors. #19249
- [ENHANCEMENT] TSDB: Add fast path for XOR chunk decompression to speed up queries. #18049
- [ENHANCEMENT] UI: Improve native histogram table formatting and add a background bar indicating the bucket count. #19332
- [ENHANCEMENT] TSDB: Add `prometheus_tsdb_head_series_pending_commit_underflow_total` to report pending-sample reservation underflows. #19470
- [PERF] AWS SD: Build RDS cluster labels once per cluster instead of once per instance. #19504
- [PERF] AWS SD: Describe RDS instances of different clusters concurrently, bounded by `request_concurrency`. #19506
- [PERF] AWS SD: Describe each ElastiCache resource once per refresh instead of twice. #19585
- [PERF] Remote read: Avoid cloning labels for sampled reads when no external labels are configured. #19503
- [PERF] Remote write: Reuse OTLP converter scratch state between requests. #19388
- [PERF] scrape: conversion from classic to native histograms should only parse start times when enabled.

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.15.0]_

### v3.15.0-rc.1 — 3.15.0-rc.1 / 2026-09-21

- Date: 2026-09-22
- Version: v3.15.0-rc.1
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.15.0-rc.1
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.15.0-rc.1
- Labels: Pre-release

- **fixed** — Avoid WAL corruption after a failed WAL write in Agent mode

- [BUGFIX] TSDB: Avoid WAL corruption after a failed WAL write in Agent mode. #19700

### v3.15.0-rc.0 — 3.15.0-rc.0 / 2026-09-09

- Date: 2026-09-14
- Version: v3.15.0-rc.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.15.0-rc.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.15.0-rc.0
- Labels: Pre-release

- **changed** — PromQL: Fix range query evaluation to prevent subqueries from evaluating past the parent's last actual step when end is not aligned to step
- **changed** — PromQL: Do not register a start timestamp reset if the start timestamp hasn't changed between subsequent samples
- **deprecated** — Logging: Deprecate --log.level flag in favor of runtime.log_level configuration
- **added** — Configuration: Allow changing the process log level through runtime.log_level on configuration reload
- **added** — Add --auto-gomemlimit.refresh-interval flag to periodically re-detect container or system memory limit and update GOMEMLIMIT at runtime
- **added** — Add support for scraping targets via Unix Domain Sockets
- **added** — Implement OM2.0 scrape format
- **changed** — Reduce TSDB head CPU utilization when initializing
- **added** — Docker SD: Add labels __meta_docker_container_image and __meta_docker_container_image_id
- **added** — Support zstd-compressed scrape responses, enabled via feature flag zstd-scrape
- **changed** — Stabilize the XOR2 float chunk encoding with storage.tsdb.chunk_encoding.floats: xor2 instead of --enable-feature=xor2-encoding
- **added** — Add prometheus_tsdb_head_appenders_created_total metric
- **added** — Add more spans to scrapes, API queries and rule evaluations for improved tracing
- **changed** — Show the effective configuration for each scrape pool on the Targets and Service Discovery pages
- **added** — Enable start time synthesis for summary _count and _sum series in scrape appender v2
- **changed** — Stop all scrape pools in parallel for faster shutdowns
- **fixed** — PromQL: Fix info() enrichment for composite expressions with mixed @/offset references or selector-free vector branches
- **fixed** — PromQL: Fix info() enrichment when input series use different subsets of identifying labels
- **fixed** — TSDB: Don't silently drop samples when head garbage collection removes a series while it is being appended to
- **fixed** — HTTP: Avoid truncating compressed responses when handlers set Content-Length

- [CHANGE] PromQL: A range query whose `end` was not aligned to `step` caused subqueries inside it to evaluate past the parent's last actual step, inflating `peakSamples` in the query stats and against the `query.max-samples` limit, and wasting storage I/O reading samples that were never used in the result. Add tests to prevent regression of the fix made in #18081. #18598
- [CHANGE] PromQL: Do not register a start timestamp reset if the start timestamp hasn't changed between subsequent samples. #19454
- [CHANGE] Logging: Deprecate `--log.level`; use `runtime.log_level` configuration to supply the default level. #19511
- [FEATURE] Configuration: Allow changing the process log level through `runtime.log_level` on configuration reload. #19511
- [FEATURE] Prometheus: Add `--auto-gomemlimit.refresh-interval` flag to periodically re-detect the container or system memory limit and update `GOMEMLIMIT` at runtime. #18843
- [FEATURE] Scraping: Add support for scraping targets via Unix Domain Sockets. #12024. #18091
- [FEATURE] scrape: Implement OM2.0 scrape format. #18606
- [ENHANCEMENT] Reduce TSDB head CPU utilization when initializing. #18001
- [ENHANCEMENT] Docker SD: Add labels `__meta_docker_container_image` and `__meta_docker_container_image_id`. #19386
- [ENHANCEMENT] Mixin: Add a p95/p99 remote-write send-batch latency panel to the remote-write dashboard. #19500
- [ENHANCEMENT] Mixin: Support native histograms in the remote-write send-batch latency panel. #19522
- [ENHANCEMENT] PromQL/TSDB: The `--enable-feature=st-storage` flag now automatically enables XOR2 float chunk encoding and ST-capable histogram chunk encoding, so you no longer need to pass `xor2-encoding` and `histograms-st-encoding` alongside it. #19518
- [ENHANCEMENT] Remote write / Alertmanager: upgrade sigv4 to v0.5.0, adding `session_name` and `tags` fields for STS AssumeRole sessions. The previously undocumented `service_name` field is now also documented. #19569
- [ENHANCEMENT] Scraping: Support zstd-compressed scrape responses, enabled via feature flag `zstd-scrape`. #19502
- [ENHANCEMENT] TSDB: Stabilize the XOR2 float chunk encoding. `--enable-feature=xor2-encoding` is deprecated; use `storage.tsdb.chunk_encoding.floats: xor2` instead. Check that other software reading the TSDB directly (e.g. Thanos sidecar) supports XOR2 before enabling. #19461
- [ENHANCEMENT] TSDB: add `prometheus_tsdb_head_appenders_created_total` metric. #19411
- [ENHANCEMENT] Tracing: add more spans to scrapes, API queries and rule evaluations. #19410
- [ENHANCEMENT] UI: Show the effective configuration for each scrape pool on the Targets and Service Discovery pages. #19384
- [ENHANCEMENT] scrape: Enable start time synthesis for summary `_count` and `_sum` series in scrape appender v2. #19323
- [ENHANCEMENT] scrape: stop all pools in parallel for faster shutdowns. #19295
- [ENHANCEMENT] storage/remote: Add undocumented failed_request_logging config field to debug log remote write V2 requests on send errors. #19249
- [ENHANCEMENT] TSDB: Add fast path for XOR chunk decompression to speed up queries. #18049
- [ENHANCEMENT] UI: Improve native histogram table formatting and add a background bar indicating the bucket count. #19332
- [ENHANCEMENT] TSDB: Add `prometheus_tsdb_head_series_pending_commit_underflow_total` to report pending-sample reservation underflows. #19470
- [PERF] AWS SD: Build RDS cluster labels once per cluster instead of once per instance. #19504
- [PERF] AWS SD: Describe RDS instances of different clusters concurrently, bounded by `request_concurrency`. #19506
- [PERF] AWS SD: Describe each ElastiCache resource once per refresh instead of twice. #19585
- [PERF] Remote read: Avoid cloning labels for sampled reads when no external labels are configured. #19503
- [PERF] Remote write: Reuse OTLP converter scratch state between requests. #19388
- [PERF] scrape: conversion from classic to native histograms should only parse start times when enabled.

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.15.0-rc.0]_

### v3.13.3 — 3.13.3 / 2026-09-07

- Date: 2026-09-07
- Version: v3.13.3
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.3
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.3

- **security** — Bump github.com/klauspost/compress to v1.18.7 (GO-2026-5841) and golang.org/x/crypto to v0.55.0 (GO-2026-6303)
- **fixed** — Docker SD: Fix panic in Docker Swarm service discovery when a service runs as a plugin or network-attachment
- **fixed** — PromQL: Fix case-insensitive regex label matchers silently dropping matching values
- **fixed** — Scrape: Fix scrape manager spinning at 100% CPU on shutdown
- **fixed** — Alerting: Fix 100% CPU usage on shutdown that could delay graceful shutdown and trigger timeout-based kills
- **fixed** — TSDB: Fix out-of-order queries blocking compaction for hours, causing memory usage to grow
- **fixed** — TSDB: Fix deleted series causing missing samples and errors after restart
- **fixed** — TSDB: Fix goroutine and file handle leaks when Prometheus fails to open a corrupt TSDB

- [SECURITY] Bump github.com/klauspost/compress to v1.18.7 (GO-2026-5841) and golang.org/x/crypto to v0.55.0 (GO-2026-6303).
- [BUGFIX] Docker SD: Fix panic in Docker Swarm service discovery when a service runs as a plugin or network-attachment. #19102
- [BUGFIX] PromQL: Fix case-insensitive regex label matchers silently dropping matching values. #19167
- [BUGFIX] Scrape: Fix scrape manager spinning at 100% CPU on shutdown. #19149
- [BUGFIX] Alerting: Fix 100% CPU usage on shutdown that could delay graceful shutdown and trigger timeout-based kills. #17859
- [BUGFIX] TSDB: Fix out-of-order queries blocking compaction for hours, causing memory usage to grow. #19013
- [BUGFIX] TSDB: Fix deleted series causing missing samples and errors after restart. #19140
- [BUGFIX] TSDB: Fix goroutine and file handle leaks when Prometheus fails to open a corrupt TSDB. On Windows, the leaked directory handle also prevented TSDB directory removal. #18291

### v3.14.0 — 3.14.0 / 2026-08-17

- Date: 2026-08-18
- Version: v3.14.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.14.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.14.0

- **deprecated** — Deprecate the `stats` query parameter of `/api/v1/query` and `/api/v1/query_range` for values other than `true` and `all`; other values will be rejected in the next major release
- **changed** — API: `/api/v1/status/config` now correctly shows `separator: ""` and `replacement: ""` in relabel configs when explicitly set to empty
- **changed** — Discovery/Hetzner: Drop the `__meta_hetzner_datacenter` label for `hcloud` targets following its removal from the Hetzner Cloud API
- **changed** — PromQL: Enable duration expressions by default and make the `promql-duration-expr` feature flag a no-op
- **changed** — PromQL: Promote `first_over_time` to stable, no longer requiring the `promql-experimental-functions` feature flag
- **added** — Discovery: Add Oracle Cloud Infrastructure compute service discovery (`oci_sd_configs`)
- **added** — PromQL: Add experimental `start_timestamp(instant-vector)` function returning the start timestamp of each sample in the given vector
- **added** — PromQL: Allow `rate()` and `increase()` to use start timestamps as an alternative for rate extrapolation
- **added** — TSDB: Add experimental support for encoding start timestamps in histograms and float histograms
- **changed** — OTLP: Emit a warning when OTLP attribute names collide into the same Prometheus label after sanitization and expose the `prometheus_api_otlp_translation_warnings_total` counter
- **added** — Promtool: Add `--remote-write.path` flag to `push metrics` for backends that use a non-default remote-write endpoint
- **changed** — Remote write: Forward histogram start timestamps in the remote write V2 protocol
- **added** — TSDB: Add `prometheus_tsdb_head_native_histogram_series` and `prometheus_tsdb_head_native_histogram_buckets` gauges tracking native histogram series and buckets in the head
- **changed** — UI: Add syntax highlighting, autocompletion, and linting for PromQL duration expressions in range selectors and subqueries
- **added** — UI: Add copy button next to rule names on the Rules and Alerts pages
- **changed** — UI: Improve rule group title contrast on the Rules page
- **fixed** — Speed up regex label matchers matching a set of literal values
- **fixed** — Remote read: Improve remote read throughput by removing unnecessary per-write flushing
- **fixed** — Scrape: Parse text and OpenMetrics formats without recursion, preventing stack overflow from deeply nested or malicious exposition input

- [CHANGE] API: Deprecate the `stats` query parameter of `/api/v1/query` and `/api/v1/query_range` for values other than `true` and `all`. Other values still enable basic statistics but now return a deprecation warning; they will be rejected in the next major release. #19124
- [CHANGE] API: `/api/v1/status/config` now correctly shows `separator: ""` and `replacement: ""` in relabel configs when explicitly set to empty, instead of omitting them. #18653
- [CHANGE] Discovery/Hetzner: Drop the `__meta_hetzner_datacenter` label for `hcloud` targets, following its removal from the Hetzner Cloud API. #19269
- [CHANGE] PromQL: Enable duration expressions by default. The `promql-duration-expr` feature flag is now a no-op. #19033
- [CHANGE] PromQL: Promote `first_over_time` to stable. It no longer requires the `promql-experimental-functions` feature flag. #19093
- [FEATURE] Discovery: Add Oracle Cloud Infrastructure compute service discovery (`oci_sd_configs`). #18919
- [FEATURE] PromQL: Add experimental `start_timestamp(instant-vector)` function returning the start timestamp of each sample in the given vector. Requires the `use-start-timestamps` feature flag. #19089
- [FEATURE] PromQL: Allow `rate()` and `increase()` to use start timestamps as an alternative for rate extrapolation. Hidden behind the `use-start-timestamps` feature flag. #18619
- [FEATURE] TSDB: Add experimental support for encoding start timestamps in histograms and float histograms. Hidden behind the `histograms-st-encoding` feature flag. #18609
- [ENHANCEMENT] OTLP: Emit a warning when OTLP attribute names collide into the same Prometheus label after sanitization (e.g. `k8s.pod.name` and `k8s_pod_name` both become `k8s_pod_name`), and expose the `prometheus_api_otlp_translation_warnings_total` counter labelled by `category` to track such warnings. #18957
- [ENHANCEMENT] Promtool: Add `--remote-write.path` flag to `push metrics` for backends that use a non-default remote-write endpoint. #19086
- [ENHANCEMENT] Remote write: Forward histogram start timestamps in the remote write V2 protocol. #18903
- [ENHANCEMENT] TSDB: Add `prometheus_tsdb_head_native_histogram_series` and `prometheus_tsdb_head_native_histogram_buckets` gauges tracking the number of native histogram series and buckets in the head. #19170
- [ENHANCEMENT] UI: Add syntax highlighting, autocompletion, and linting for PromQL duration expressions (`step()`, `range()`, `min_of()`, `max_of()`) in range selectors and subqueries. #18625
- [ENHANCEMENT] UI: Add copy button next to rule names on the Rules and Alerts pages. #18706
- [ENHANCEMENT] UI: Improve rule group title contrast on the Rules page. #19181
- [PERF] Speed up regex label matchers matching a set of literal values (e.g. `{job=~"foo|bar|baz"}`). #18833
- [PERF] Remote read: Improve remote read throughput by removing unnecessary per-write flushing. #18470
- [PERF] Scrape: Parse text and OpenMetrics formats without recursion, preventing stack overflow from deeply nested or malicious exposition input. #19143
- [PERF] Scrape: Reduce native histogram scrape parsing allocations by ~49%. #19282
- [PERF] TSDB: Speed up queries on series with many in-memory chunks. #18300
- [BUGFIX] Alerting: Fix 100% CPU usage on shutdown that could delay graceful shutdown and trigger timeout-based kills. #17859
- [BUGFIX] Discovery/AWS: Stop `promtool check config` from making AWS metadata service (IMDS) network calls when the `region` field is omitted in EC2, ECS, RDS, MSK, ElastiCache, and Lightsail service discovery configs. #19037
- [BUGFIX] Discovery/Docker: Set a request timeout for `docker_sd` and `dockerswarm_sd` on `unix`, `npipe`, and `tcp` hosts. Previously an unresponsive daemon could freeze discovery indefinitely, silently pinning targets to a stale snapshot. #19237
- [BUGFIX] Discovery/Docker: Fix panic in Docker Swarm service discovery when a service runs as a plugin or network-attachment. #19102
- [BUGFIX] Discovery/Docker: Fix discov

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.14.0]_

### v3.14.0-rc.0 — 3.14.0-rc.0 / 2026-08-06

- Date: 2026-08-11
- Version: v3.14.0-rc.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.14.0-rc.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.14.0-rc.0
- Labels: Pre-release

- **deprecated** — Deprecate the `stats` query parameter of `/api/v1/query` and `/api/v1/query_range` for values other than `true` and `all`; other values will be rejected in the next major release
- **changed** — API `/api/v1/status/config` now correctly shows `separator: ""` and `replacement: ""` in relabel configs when explicitly set to empty
- **changed** — Discovery/Hetzner: Drop the `__meta_hetzner_datacenter` label for `hcloud` targets following its removal from the Hetzner Cloud API
- **changed** — PromQL: Enable duration expressions by default; the `promql-duration-expr` feature flag is now a no-op
- **changed** — PromQL: Promote `first_over_time` to stable and no longer require the `promql-experimental-functions` feature flag
- **added** — Discovery: Add Oracle Cloud Infrastructure compute service discovery (`oci_sd_configs`)
- **added** — PromQL: Add experimental `start_timestamp(instant-vector)` function returning the start timestamp of each sample in the given vector
- **added** — PromQL: Allow `rate()` and `increase()` to use start timestamps as an alternative for rate extrapolation
- **added** — TSDB: Add experimental support for encoding start timestamps in histograms and float histograms
- **changed** — OTLP: Emit a warning when OTLP attribute names collide into the same Prometheus label after sanitization and expose the `prometheus_api_otlp_translation_warnings_total` counter
- **added** — Promtool: Add `--remote-write.path` flag to `push metrics` for backends that use a non-default remote-write endpoint
- **changed** — Remote write: Forward histogram start timestamps in the remote write V2 protocol
- **added** — TSDB: Add `prometheus_tsdb_head_native_histogram_series` and `prometheus_tsdb_head_native_histogram_buckets` gauges tracking native histogram series and buckets in the head
- **changed** — UI: Add syntax highlighting, autocompletion, and linting for PromQL duration expressions in range selectors and subqueries
- **added** — UI: Add copy button next to rule names on the Rules and Alerts pages
- **changed** — UI: Improve rule group title contrast on the Rules page
- **fixed** — Speed up regex label matchers matching a set of literal values
- **changed** — Remote read: Improve remote read throughput by removing unnecessary per-write flushing
- **fixed** — Scrape: Parse text and OpenMetrics formats without recursion, preventing stack overflow from deeply nested or malicious exposition input
- **fixed** — Scrape: Reduce native histogram scrape parsing allocations by approximately 49%

- [CHANGE] API: Deprecate the `stats` query parameter of `/api/v1/query` and `/api/v1/query_range` for values other than `true` and `all`. Other values still enable basic statistics but now return a deprecation warning; they will be rejected in the next major release. #19124
- [CHANGE] API: `/api/v1/status/config` now correctly shows `separator: ""` and `replacement: ""` in relabel configs when explicitly set to empty, instead of omitting them. #18653
- [CHANGE] Discovery/Hetzner: Drop the `__meta_hetzner_datacenter` label for `hcloud` targets, following its removal from the Hetzner Cloud API. #19269
- [CHANGE] PromQL: Enable duration expressions by default. The `promql-duration-expr` feature flag is now a no-op. #19033
- [CHANGE] PromQL: Promote `first_over_time` to stable. It no longer requires the `promql-experimental-functions` feature flag. #19093
- [FEATURE] Discovery: Add Oracle Cloud Infrastructure compute service discovery (`oci_sd_configs`). #18919
- [FEATURE] PromQL: Add experimental `start_timestamp(instant-vector)` function returning the start timestamp of each sample in the given vector. Requires the `use-start-timestamps` feature flag. #19089
- [FEATURE] PromQL: Allow `rate()` and `increase()` to use start timestamps as an alternative for rate extrapolation. Hidden behind the `use-start-timestamps` feature flag. #18619
- [FEATURE] TSDB: Add experimental support for encoding start timestamps in histograms and float histograms. Hidden behind the `histograms-st-encoding` feature flag. #18609
- [ENHANCEMENT] OTLP: Emit a warning when OTLP attribute names collide into the same Prometheus label after sanitization (e.g. `k8s.pod.name` and `k8s_pod_name` both become `k8s_pod_name`), and expose the `prometheus_api_otlp_translation_warnings_total` counter labelled by `category` to track such warnings. #18957
- [ENHANCEMENT] Promtool: Add `--remote-write.path` flag to `push metrics` for backends that use a non-default remote-write endpoint. #19086
- [ENHANCEMENT] Remote write: Forward histogram start timestamps in the remote write V2 protocol. #18903
- [ENHANCEMENT] TSDB: Add `prometheus_tsdb_head_native_histogram_series` and `prometheus_tsdb_head_native_histogram_buckets` gauges tracking the number of native histogram series and buckets in the head. #19170
- [ENHANCEMENT] UI: Add syntax highlighting, autocompletion, and linting for PromQL duration expressions (`step()`, `range()`, `min_of()`, `max_of()`) in range selectors and subqueries. #18625
- [ENHANCEMENT] UI: Add copy button next to rule names on the Rules and Alerts pages. #18706
- [ENHANCEMENT] UI: Improve rule group title contrast on the Rules page. #19181
- [PERF] Speed up regex label matchers matching a set of literal values (e.g. `{job=~"foo|bar|baz"}`). #18833
- [PERF] Remote read: Improve remote read throughput by removing unnecessary per-write flushing. #18470
- [PERF] Scrape: Parse text and OpenMetrics formats without recursion, preventing stack overflow from deeply nested or malicious exposition input. #19143
- [PERF] Scrape: Reduce native histogram scrape parsing allocations by ~49%. #19282
- [PERF] TSDB: Speed up queries on series with many in-memory chunks. #18300
- [BUGFIX] Alerting: Fix 100% CPU usage on shutdown that could delay graceful shutdown and trigger timeout-based kills. #17859
- [BUGFIX] Discovery/AWS: Stop `promtool check config` from making AWS metadata service (IMDS) network calls when the `region` field is omitted in EC2, ECS, RDS, MSK, ElastiCache, and Lightsail service discovery configs. #19037
- [BUGFIX] Discovery/Docker: Set a request timeout for `docker_sd` and `dockerswarm_sd` on `unix`, `npipe`, and `tcp` hosts. Previously an unresponsive daemon could freeze discovery indefinitely, silently pinning targets to a stale snapshot. #19237
- [BUGFIX] Discovery/Docker: Fix panic in Docker Swarm service discovery when a service runs as a plugin or network-attachment. #19102
- [BUGFIX] Discovery/Docker: Fix discov

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.14.0-rc.0]_

### v3.13.2 — 3.13.2 / 2026-07-29

- Date: 2026-07-30
- Version: v3.13.2
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.2
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.2

- **security** — Bump golang.org/x/text to v0.39.0 (CVE-2026-56852) and google.golang.org/grpc to v1.82.1 (GHSA-hrxh-6v49-42gf)
- **fixed** — PromQL: Preallocate the active query tracker file to avoid SIGBUS crashes when the data disk is full

##### What's Changed

- [SECURITY] Bump golang.org/x/text to v0.39.0 (CVE-2026-56852) and google.golang.org/grpc to v1.82.1 (GHSA-hrxh-6v49-42gf). #19290 by @krajorama
- [BUGFIX] PromQL: Preallocate the active query tracker file to avoid SIGBUS crashes when the data disk is full. #19289 by @akshajrawat

**Full Changelog**: https://github.com/prometheus/prometheus/compare/v3.13.1...v3.13.2

### v3.13.1 — 3.13.1 / 2026-07-10

- Date: 2026-07-10
- Version: v3.13.1
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.1
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.1

- **fixed** — TSDB: Fix the head-chunk cache returning samples from the wrong chunk, or spurious not-found errors, to range queries after head-chunk truncation

This is a bugfix release for 3.13 LTS.

- [BUGFIX] TSDB: Fix the head-chunk cache returning samples from the wrong chunk, or spurious not-found errors, to range queries after head-chunk truncation. #19134

### v3.5.5 — 3.5.5 / 2026-07-09

- Date: 2026-07-09
- Version: v3.5.5
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.5.5
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.5.5

- **security** — Bump sanitize-html to v2.17.5 to fix CVE-2026-53606 in UI dependency

This release is built with Go 1.25.12 and fixes a security issue in a UI dependency.

- [SECURITY] UI: Bump `sanitize-html` to v2.17.5 to fix CVE-2026-53606. #19060

### v3.13.0-rc.0 — 3.13.0-rc.0 / 2026-06-18

- Date: 2026-07-09
- Version: v3.13.0-rc.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0-rc.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.0-rc.0
- Labels: Pre-release

- **security** — Bump sanitize-html to fix a cross-site scripting vulnerability (CVE-2026-44990)
- **changed** — Use SHA-256 instead of SHA-1 to generate rule group pagination tokens
- **security** — Credentials (Authorization header, basic auth, bearer token, OAuth2, configured headers) are no longer forwarded when following a redirect to a different host; affects scraping, remote read/write, alerting, and service discovery (CVE-2025-4673 CVE-2023-45289)
- **changed** — Relative file paths in the file passed to --http.config.file are now resolved relative to that config file's directory instead of its parent directory
- **changed** — Rename the min() and max() duration-expression functions to min_of() and max_of() to avoid confusion with the min and max aggregate operators
- **added** — Add experimental search endpoints to search metric names, label names, and label values
- **added** — Add ability to filter RDS instances in Discovery/AWS
- **added** — Add min_of(a, b) and max_of(a, b) scalar experimental functions, returning the smaller or larger of two scalar values
- **added** — Add support for smoothed/anchored rate with native histograms
- **added** — Expose per-query samplesRead in the query stats response and add the prometheus_engine_query_samples_read_total engine counter
- **added** — Add __convert_classic_histograms_to_nhcb__ internal label to allow per-target override of convert_classic_histograms_to_nhcb scrape configuration via relabeling
- **added** — Add storage.tsdb.chunk_encoding.floats configuration field to select float chunk encoding at runtime
- **added** — Add Certificate support for ingesting data into an Azure Monitor Workspace in remote_write
- **added** — Add __always_scrape_classic_histograms__ and __scrape_native_histograms__ internal labels to allow per-target override of scrape configuration via relabeling
- **changed** — Container images are now also published to the GitHub Container Registry (ghcr.io)
- **changed** — Prettify fill_left(x) fill_right(x) as fill(x) when both fill values are equal
- **changed** — Improve autocompletion after closing a function bracket
- **fixed** — Fix failure when processing an AWS RDS cluster without instances
- **fixed** — Fix race condition in initTime that could cause ErrOutOfBounds
- **fixed** — Fix range query whose end was not aligned to step causing subqueries to evaluate past the parent's last actual step
- **fixed** — Fix range query containing an at-modifier-unsafe function over a range-vector with an @ modifier under-counting totalQueryableSamples
- **fixed** — Fix fill_left/fill_right producing missing samples in range queries when using group_left/group_right

- [SECURITY] UI: Bump `sanitize-html` to fix a cross-site scripting vulnerability (CVE-2026-44990). #18697
- [CHANGE] API: Use SHA-256 instead of SHA-1 to generate rule group pagination tokens. #18927
- [CHANGE] HTTP clients: Credentials (Authorization header, basic auth, bearer token, OAuth2, configured headers) are no longer forwarded when following a redirect to a different host; affects scraping, remote read/write, alerting, and service discovery. Via prometheus/common v0.69.0 (CVE-2025-4673 CVE-2023-45289). #18949
- [CHANGE] promtool: Relative file paths in the file passed to `--http.config.file` are now resolved relative to that config file's directory instead of its parent directory. Via prometheus/common v0.69.0. #18949
- [CHANGE] PromQL: Rename the `min()` and `max()` duration-expression functions (experimental feature flag `experimental-duration-expr`) to `min_of()` and `max_of()` to avoid confusion with the `min` and `max` aggregate operators. #18687
- [FEATURE] API: Add experimental search endpoints to search metric names, label names, and label values. #18573
- [FEATURE] Discovery/AWS: Add ability to filter RDS instances. #18859
- [FEATURE] PromQL: Add `min_of(a, b)` and `max_of(a, b)` scalar experimental functions, returning the smaller or larger of two scalar values. #18687
- [FEATURE] PromQL: Add support for smoothed/anchored rate with native histograms. #18564
- [FEATURE] PromQL: Expose per-query `samplesRead` (and `samplesReadPerStep` with `stats=all` and the `promql-per-step-stats` feature flag) in the query stats response, and add the `prometheus_engine_query_samples_read_total` engine counter. `samplesRead` reflects storage I/O distinct from `totalQueryableSamples`, which counts samples loaded into the evaluator (and so over-counts when a sample is reused across multiple range-vector windows). #18081
- [FEATURE] Scrape: Add `__convert_classic_histograms_to_nhcb__` internal label to allow per-target override of `convert_classic_histograms_to_nhcb` scrape configuration via relabeling. #18840
- [FEATURE] TSDB: Add `storage.tsdb.chunk_encoding.floats` configuration field to select float chunk encoding (`xor` or `xor2`) at runtime, independently of the `--enable-feature=xor2-encoding` flag. #18769
- [FEATURE] remote_write: Add Certificate support for ingesting data into an Azure Monitor Workspace. #18217
- [FEATURE] Scrape: Add `__always_scrape_classic_histograms__` and `__scrape_native_histograms__` internal labels to allow per-target override of the `always_scrape_classic_histograms` and `scrape_native_histograms` scrape configuration via relabeling. #18929
- [ENHANCEMENT] Release: Container images are now also published to the GitHub Container Registry (ghcr.io). #18791
- [ENHANCEMENT] PromQL: Prettify `fill_left(x) fill_right(x)` as `fill(x)` when both fill values are equal. #18851
- [ENHANCEMENT] UI: Improve autocompletion after closing a function bracket. #18894
- [PERF] Labels: Add case-insensitive prefix matching to speed up evaluation of long case-insensitive regular expressions (up to ~2x faster). #18540
- [PERF] TSDB: Reduce per-sample overhead in chunk population, speeding up affected queries by ~12-15% in benchmarks. #18699
- [PERF] TSDB: Eliminate unnecessary heap allocations in the V2 histogram WAL decoder, reducing allocations by up to 50% and memory by up to 10% for deployments using native histograms with created-timestamp storage enabled (`--enable-feature=created-timestamp-zero-ingestion`). #18813
- [BUGFIX] Discovery/AWS: Fix failure when processing an AWS RDS cluster without instances. #18845
- [BUGFIX] Fix race condition in initTime that could cause ErrOutOfBounds. #18629
- [BUGFIX] PromQL: A range query whose `end` was not aligned to `step` caused subqueries inside it to evaluate past the parent's last actual step, inflating `peakSamples` in the query stats and against the `query.max-samples` limit, and wasting storage I/O reading samples that were never used in the

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0-rc.0]_

### v3.13.0 — 3.13.0 / 2026-07-01

- Date: 2026-07-01
- Version: v3.13.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.0

- **security** — Bump sanitize-html to fix a cross-site scripting vulnerability (CVE-2026-44990)
- **changed** — Third-party npm dependency licenses are now embedded in the Prometheus binary and served at /assets/third-party-licenses.txt
- **changed** — Use SHA-256 instead of SHA-1 to generate rule group pagination tokens
- **security** — Credentials are no longer forwarded when following a redirect to a different host in HTTP clients (CVE-2025-4673 CVE-2023-45289)
- **changed** — Relative file paths in the file passed to --http.config.file are now resolved relative to that config file's directory instead of its parent directory
- **changed** — Rename the min() and max() duration-expression functions to min_of() and max_of() to avoid confusion with the min and max aggregate operators
- **added** — Add experimental search endpoints to search metric names, label names, and label values
- **added** — Add ability to filter RDS instances in Discovery/AWS
- **added** — Add min_of(a, b) and max_of(a, b) scalar experimental functions
- **added** — Add support for smoothed/anchored rate with native histograms
- **added** — Expose per-query samplesRead in the query stats response and add the prometheus_engine_query_samples_read_total engine counter
- **added** — Add __convert_classic_histograms_to_nhcb__ internal label to allow per-target override of convert_classic_histograms_to_nhcb scrape configuration via relabeling
- **added** — Add storage.tsdb.chunk_encoding.floats configuration field to select float chunk encoding at runtime
- **added** — Add Certificate support for ingesting data into an Azure Monitor Workspace in remote_write
- **added** — Add __always_scrape_classic_histograms__ and __scrape_native_histograms__ internal labels to allow per-target override of scrape configuration via relabeling
- **changed** — Container images are now also published to the GitHub Container Registry (ghcr.io)
- **changed** — Prettify fill_left(x) fill_right(x) as fill(x) when both fill values are equal
- **fixed** — Fix failure when processing an AWS RDS cluster without instances
- **fixed** — Fix race condition in initTime that could cause ErrOutOfBounds
- **fixed** — Fix range query with end not aligned to step causing subqueries to evaluate past the parent's last actual step
- **fixed** — Fix range query containing an at-modifier-unsafe function over a range-vector with an @ modifier under-counting totalQueryableSamples

This is a Long Term Support [LTS](https://prometheus.io/docs/introduction/release-cycle/) release.

- [SECURITY] UI: Bump `sanitize-html` to fix a cross-site scripting vulnerability (CVE-2026-44990). #18697
- [CHANGE] UI: Third-party npm dependency licenses are now embedded in the Prometheus binary and served at `/assets/third-party-licenses.txt`, replacing the `npm_licenses.tar.bz2` archive previously shipped in release tarballs and container images. #18997
- [CHANGE] API: Use SHA-256 instead of SHA-1 to generate rule group pagination tokens. #18927
- [CHANGE] HTTP clients: Credentials (Authorization header, basic auth, bearer token, OAuth2, configured headers) are no longer forwarded when following a redirect to a different host; affects scraping, remote read/write, alerting, and service discovery. Via prometheus/common v0.69.0 (CVE-2025-4673 CVE-2023-45289). #18949
- [CHANGE] promtool: Relative file paths in the file passed to `--http.config.file` are now resolved relative to that config file's directory instead of its parent directory. Via prometheus/common v0.69.0. #18949
- [CHANGE] PromQL: Rename the `min()` and `max()` duration-expression functions (experimental feature flag `experimental-duration-expr`) to `min_of()` and `max_of()` to avoid confusion with the `min` and `max` aggregate operators. #18687
- [FEATURE] API: Add experimental search endpoints to search metric names, label names, and label values. #18573
- [FEATURE] Discovery/AWS: Add ability to filter RDS instances. #18859
- [FEATURE] PromQL: Add `min_of(a, b)` and `max_of(a, b)` scalar experimental functions, returning the smaller or larger of two scalar values. #18687
- [FEATURE] PromQL: Add support for smoothed/anchored rate with native histograms. #18564
- [FEATURE] PromQL: Expose per-query `samplesRead` (and `samplesReadPerStep` with `stats=all` and the `promql-per-step-stats` feature flag) in the query stats response, and add the `prometheus_engine_query_samples_read_total` engine counter. `samplesRead` reflects storage I/O distinct from `totalQueryableSamples`, which counts samples loaded into the evaluator (and so over-counts when a sample is reused across multiple range-vector windows). #18081
- [FEATURE] Scrape: Add `__convert_classic_histograms_to_nhcb__` internal label to allow per-target override of `convert_classic_histograms_to_nhcb` scrape configuration via relabeling. #18840
- [FEATURE] TSDB: Add `storage.tsdb.chunk_encoding.floats` configuration field to select float chunk encoding (`xor` or `xor2`) at runtime, independently of the `--enable-feature=xor2-encoding` flag. #18769
- [FEATURE] remote_write: Add Certificate support for ingesting data into an Azure Monitor Workspace. #18217
- [FEATURE] Scrape: Add `__always_scrape_classic_histograms__` and `__scrape_native_histograms__` internal labels to allow per-target override of the `always_scrape_classic_histograms` and `scrape_native_histograms` scrape configuration via relabeling. #18929
- [ENHANCEMENT] Release: Container images are now also published to the GitHub Container Registry (ghcr.io). #18791
- [ENHANCEMENT] PromQL: Prettify `fill_left(x) fill_right(x)` as `fill(x)` when both fill values are equal. #18851
- [ENHANCEMENT] UI: Improve autocompletion after closing a function bracket. #18894
- [PERF] Labels: Add case-insensitive prefix matching to speed up evaluation of long case-insensitive regular expressions (up to ~2x faster). #18540
- [PERF] TSDB: Reduce per-sample overhead in chunk population, speeding up affected queries by ~12-15% in benchmarks. #18699
- [PERF] TSDB: Eliminate unnecessary heap allocations in the V2 histogram WAL decoder, reducing allocations by up to 50% and memory by up to 10% for deployments using native histograms with created-timestamp storage enabled (`--enable-feature=created-timestamp-zero-ingestion`). #18813
- [BUGFIX] Discovery/AWS: Fix failure when processing an AWS RDS cluster without instances. #18845
- [BUGFIX] Fix race cond

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0]_

### v3.13.0-rc.1 — 3.13.0-rc.1 / 2026-06-22

- Date: 2026-06-22
- Version: v3.13.0-rc.1
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0-rc.1
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.13.0-rc.1
- Labels: Pre-release

- **security** — Bump sanitize-html to fix a cross-site scripting vulnerability (CVE-2026-44990)
- **changed** — Use SHA-256 instead of SHA-1 to generate rule group pagination tokens
- **security** — Credentials (Authorization header, basic auth, bearer token, OAuth2, configured headers) are no longer forwarded when following a redirect to a different host; affects scraping, remote read/write, alerting, and service discovery (CVE-2025-4673 CVE-2023-45289)
- **changed** — Relative file paths in the file passed to promtool --http.config.file are now resolved relative to that config file's directory instead of its parent directory
- **changed** — Rename the min() and max() duration-expression functions (experimental feature flag experimental-duration-expr) to min_of() and max_of() to avoid confusion with the min and max aggregate operators
- **added** — Add experimental search endpoints to search metric names, label names, and label values
- **added** — Add ability to filter RDS instances in AWS Discovery
- **added** — Add min_of(a, b) and max_of(a, b) scalar experimental functions, returning the smaller or larger of two scalar values
- **added** — Add support for smoothed/anchored rate with native histograms
- **added** — Expose per-query samplesRead (and samplesReadPerStep with stats=all and the promql-per-step-stats feature flag) in the query stats response, and add the prometheus_engine_query_samples_read_total engine counter
- **added** — Add __convert_classic_histograms_to_nhcb__ internal label to allow per-target override of convert_classic_histograms_to_nhcb scrape configuration via relabeling
- **added** — Add storage.tsdb.chunk_encoding.floats configuration field to select float chunk encoding (xor or xor2) at runtime, independently of the --enable-feature=xor2-encoding flag
- **added** — Add Certificate support for ingesting data into an Azure Monitor Workspace in remote_write
- **added** — Add __always_scrape_classic_histograms__ and __scrape_native_histograms__ internal labels to allow per-target override of the always_scrape_classic_histograms and scrape_native_histograms scrape configuration via relabeling
- **changed** — Third-party npm dependency licenses are now embedded in the Prometheus binary and served at /assets/third-party-licenses.txt, replacing the npm_licenses.tar.bz2 archive previously shipped in release tarballs and container images
- **changed** — Container images are now also published to the GitHub Container Registry (ghcr.io)
- **changed** — Prettify fill_left(x) fill_right(x) as fill(x) when both fill values are equal
- **changed** — Improve autocompletion after closing a function bracket in the UI
- **fixed** — Fix failure when processing an AWS RDS cluster without instances in Discovery/AWS
- **fixed** — Fix race condition in initTime that could cause ErrOutOfBounds

Release notes of the 3.13-rc.1 release:

The 3.13.0-rc.0 release was only partially successful due to the migration from NPM to PNPM and subsequent CI issues, so most of the changes in this release candidate are CI/build-related. The only user-facing change is:

- [CHANGE] UI: Third-party npm dependency licenses are now embedded in the Prometheus binary and served at `/assets/third-party-licenses.txt`, replacing the `npm_licenses.tar.bz2` archive previously shipped in release tarballs and container images. #18997

Release notes of the 3.13-rc.0 release, as it was not published in partial state:

- [SECURITY] UI: Bump `sanitize-html` to fix a cross-site scripting vulnerability (CVE-2026-44990). #18697
- [CHANGE] API: Use SHA-256 instead of SHA-1 to generate rule group pagination tokens. #18927
- [CHANGE] HTTP clients: Credentials (Authorization header, basic auth, bearer token, OAuth2, configured headers) are no longer forwarded when following a redirect to a different host; affects scraping, remote read/write, alerting, and service discovery. Via prometheus/common v0.69.0 (CVE-2025-4673 CVE-2023-45289). #18949
- [CHANGE] promtool: Relative file paths in the file passed to `--http.config.file` are now resolved relative to that config file's directory instead of its parent directory. Via prometheus/common v0.69.0. #18949
- [CHANGE] PromQL: Rename the `min()` and `max()` duration-expression functions (experimental feature flag `experimental-duration-expr`) to `min_of()` and `max_of()` to avoid confusion with the `min` and `max` aggregate operators. #18687
- [FEATURE] API: Add experimental search endpoints to search metric names, label names, and label values. #18573
- [FEATURE] Discovery/AWS: Add ability to filter RDS instances. #18859
- [FEATURE] PromQL: Add `min_of(a, b)` and `max_of(a, b)` scalar experimental functions, returning the smaller or larger of two scalar values. #18687
- [FEATURE] PromQL: Add support for smoothed/anchored rate with native histograms. #18564
- [FEATURE] PromQL: Expose per-query `samplesRead` (and `samplesReadPerStep` with `stats=all` and the `promql-per-step-stats` feature flag) in the query stats response, and add the `prometheus_engine_query_samples_read_total` engine counter. `samplesRead` reflects storage I/O distinct from `totalQueryableSamples`, which counts samples loaded into the evaluator (and so over-counts when a sample is reused across multiple range-vector windows). #18081
- [FEATURE] Scrape: Add `__convert_classic_histograms_to_nhcb__` internal label to allow per-target override of `convert_classic_histograms_to_nhcb` scrape configuration via relabeling. #18840
- [FEATURE] TSDB: Add `storage.tsdb.chunk_encoding.floats` configuration field to select float chunk encoding (`xor` or `xor2`) at runtime, independently of the `--enable-feature=xor2-encoding` flag. #18769
- [FEATURE] remote_write: Add Certificate support for ingesting data into an Azure Monitor Workspace. #18217
- [FEATURE] Scrape: Add `__always_scrape_classic_histograms__` and `__scrape_native_histograms__` internal labels to allow per-target override of the `always_scrape_classic_histograms` and `scrape_native_histograms` scrape configuration via relabeling. #18929
- [ENHANCEMENT] Release: Container images are now also published to the GitHub Container Registry (ghcr.io). #18791
- [ENHANCEMENT] PromQL: Prettify `fill_left(x) fill_right(x)` as `fill(x)` when both fill values are equal. #18851
- [ENHANCEMENT] UI: Improve autocompletion after closing a function bracket. #18894
- [PERF] Labels: Add case-insensitive prefix matching to speed up evaluation of long case-insensitive regular expressions (up to ~2x faster). #18540
- [PERF] TSDB: Reduce per-sample overhead in chunk population, speeding up affected queries by ~12-15% in benchmarks. #18699
- [PERF] TSDB: Eliminate unnecessary heap allocations in the V2 histogram WAL decoder, reducing allocations by up to 50% and memory by up to 10% for deployment

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.13.0-rc.1]_

### v3.5.4 — 3.5.4 / 2026-06-17

- Date: 2026-06-17
- Version: v3.5.4
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.5.4
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.5.4

- **security** — Fix secrets being exposed in plaintext via /-/config endpoint in STACKIT SD
- **security** — Bump golang.org/x/net to v0.55.0 and OpenTelemetry to v1.43.0 to fix reported CVEs
- **security** — Bump mantine-ui dependencies (react-router-dom, vitest, vite, postcss) to patched versions to resolve security advisories
- **added** — Container images are now also published to the GitHub Container Registry (ghcr.io)

This release fixes multiple security issues.

- [SECURITY] STACKIT SD: Fix secrets being exposed in plaintext via `/-/config` endpoint. Thanks to @August829 and @Phaxma for reporting. GHSA-39j6-789q-qxvh #18650
- [SECURITY] Dependencies: Bump `golang.org/x/net` to v0.55.0 and OpenTelemetry to v1.43.0 to fix reported CVEs (GO-2026-5026, GO-2026-4918, GO-2026-4985). #18934
- [SECURITY] UI: Bump mantine-ui dependencies (`react-router-dom`, `vitest`, `vite`, `postcss`) to their patched versions to resolve security advisories. #18935
- [ENHANCEMENT] Release: Container images are now also published to the GitHub Container Registry (ghcr.io). #18792

### v3.12.0 — 3.12.0 / 2026-05-28

- Date: 2026-05-28
- Version: v3.12.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.12.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.12.0

- **security** — Reject snappy-compressed received requests via Remote Write whose declared decoded length exceeds 32MB
- **security** — Fix secrets being exposed in plaintext via /-/config endpoint in STACKIT SD
- **added** — Add /api/v1/status/self_metrics endpoint returning the current state of the Prometheus server's own metrics
- **added** — Add DigitalOcean Managed Databases service discovery
- **added** — Add support for the aix/ppc64 compilation target
- **added** — Add Outscale VM service discovery (outscale_sd_configs) for discovering scrape targets from the Outscale Cloud API
- **added** — Emit a warning when sort, sort_by_label or sort_by_label_desc is used within range (matrix) queries
- **added** — Add start(), end(), range(), and step() experimental functions to PromQL
- **added** — Update resets() function to consider start timestamp resets, hidden behind use-start-timestamps feature flag
- **added** — Add CheckpointFromInMemorySeries option to agent.DB that enables checkpoint based on in-memory series
- **added** — Add a web interface for deleting time series and cleaning tombstones, accessible from the Status menu
- **added** — Use start timestamps for rate(), irate(), and increase() calculations, behind a feature flag use-start-timestamps
- **added** — Add feature flag st-synthesis which synthesizes unknown start timestamps for scraped cumulative metrics
- **added** — Support @st annotation in load blocks to specify per-sample start timestamps in promqltest
- **changed** — Promote auto-reload-config as stable
- **changed** — Add Start Timestamp field to all WAL Histogram samples in memory when st-storage flag is enabled
- **changed** — Add optional external_id field to AWS SD for ECS, MSK, RDS, and Elasticache
- **changed** — Allow EC2 service discovery to discover IPv6 addresses to communicate with target endpoints
- **changed** — Propagate SD target updates faster by introducing dynamic backoff interval instead of static 5s interval
- **changed** — Add --header flag to promtool query instant command
- **fixed** — Make head chunk lookup in range queries constant time instead of quadratic time

This release contains security fixes, new features (especially around PromQL and Service Discovery), performance improvements in TSDB, Start Timestamp improvements and numerous bug fixes.

Thanks to all contributors!

##### Key Highlights
*   **Security**: Two security vulnerabilities have been addressed: a denial of service in remote-write (snappy decompression limit) and a secret exposure leak in STACKIT service discovery.
*   **PromQL & Metadata**: Several features and bug fixes related to the experimental "start timestamps" support, including updates to `rate()`, `irate()`, `increase()`, and `resets()`. New experimental functions `start()`, `end()`, `range()`, and `step()` are introduced.
*   **TSDB Performance**: Optimizations in head chunk lookup (constant time) and mmap operations to reduce CPU usage.
*   **Service Discovery**: Added support for DigitalOcean Managed Databases and Outscale VM, along with improvements to AWS SD (IPv6 support for EC2, external ID support).
*   **UI**: Added a web interface for deleting time series and cleaning tombstones.

##### Changelog

- [SECURITY] Remote: Reject snappy-compressed received requests via Remote Write whose declared decoded length exceeds the 32MB. Thanks to @hibrian827 for reporting it. #18642
- [SECURITY] STACKIT SD: Fix secrets being exposed in plaintext via `/-/config` endpoint. Thanks to @August829 and @Phaxma for reporting. GHSA-39j6-789q-qxvh #18649
- [CHANGE] TSDB/Agent: Adds Start Timestamp field to all WAL Histogram samples in memory; used `st-storage` flag is enabled. #18221
- [FEATURE] API: Add `/api/v1/status/self_metrics` endpoint returning the current state of the Prometheus server's own metrics about itself as JSON. #18411
- [FEATURE] Discovery: Add DigitalOcean Managed Databases service discovery #18287
- [FEATURE] Prometheus: Add support for the aix/ppc64 compilation target #18321
- [FEATURE] Discovery: Add Outscale VM service discovery (`outscale_sd_configs`) for discovering scrape targets from the Outscale Cloud API. #18139
- [FEATURE] PromQL: Emit a warning when `sort`, `sort_by_label` or `sort_by_label_desc` is used within range (matrix) queries, as these functions do not have effect in that context. #18498
- [FEATURE] PromQL: Add `start()`, `end()`, `range()`, and `step()` experimental functions #17877
- [FEATURE] PromQL: Update `resets()` function to consider start timestamp resets. Hidden behind `use-start-timestamps` feature flag. #18627
- [FEATURE] Prometheus: Promote auto-reload-config as stable #18620
- [FEATURE] TSDB/Agent: Add `CheckpointFromInMemorySeries` option to `agent.DB` that enables checkpoint based on in-memory series. #17948
- [FEATURE] UI: Add a web interface for deleting time series and cleaning tombstones, accessible from the Status menu. #18390
- [FEATURE] PromQL: Use start timestamps for `rate()`, `irate()`, and `increase()` calculations, behind a feature flag `use-start-timestamps`. Doesn't work together with extended range selectors `anchored` and `smoothed`. #18344
- [FEATURE] Scrape: Added a feature flag `st-synthesis` which synthesizes unknown STs for scraped cumulative metrics. Useful when Remote Writing 2.0 with delta or Otel-based backends. #18279
- [FEATURE] promqltest: support `@st` annotation in `load` blocks to specify per-sample start timestamps. #18360
- [ENHANCEMENT] API: reject concurrent fgprof profiles. #18651
- [ENHANCEMENT] AWS SD: Add optional `external_id` field to ECS/MSK/RDS/Elasticache. #18579
- [ENHANCEMENT] AWS SD: Add optional `external_id` field. #17171
- [ENHANCEMENT] Discovery: Propagate SD target updates faster by introducing dynamic backoff interval instead of static 5s interval for throttling. #18187
- [ENHANCEMENT] Promtool: Add `--header` flag to `query instant` command, matching existing `query range` behaviour. #18418
- [ENHANCEMENT]: AWS SD: Allows EC2 service discovery to discover IPv6 addresses to communicate with target endpoints. The private IPv4 addr

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.12.0]_

### v3.12.0-rc.0 — 3.12.0-rc.0 / 2026-05-19

- Date: 2026-05-19
- Version: v3.12.0-rc.0
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.12.0-rc.0
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.12.0-rc.0
- Labels: Pre-release

- **security** — Reject snappy-compressed received requests via Remote Write whose declared decoded length exceeds 32MB
- **security** — Fix secrets being exposed in plaintext via /-/config endpoint in STACKIT SD
- **added** — Add /api/v1/status/self_metrics endpoint returning the current state of the Prometheus server's own metrics
- **added** — Add DigitalOcean Managed Databases service discovery
- **added** — Add support for the aix/ppc64 compilation target
- **added** — Add Outscale VM service discovery (outscale_sd_configs) for discovering scrape targets from the Outscale Cloud API
- **added** — Add start(), end(), range(), and step() experimental functions to PromQL
- **added** — Add web interface for deleting time series and cleaning tombstones, accessible from the Status menu
- **added** — Add feature flag st-synthesis which synthesizes unknown STs for scraped cumulative metrics
- **changed** — Add Start Timestamp field to all WAL Histogram samples in memory when st-storage flag is enabled
- **changed** — Update resets() function to consider start timestamp resets, hidden behind use-start-timestamps feature flag
- **changed** — Use start timestamps for rate(), irate(), and increase() calculations, behind feature flag use-start-timestamps
- **changed** — Promote auto-reload-config as stable
- **changed** — Update rate(), irate(), increase(), and resets() functions for experimental start timestamps support
- **added** — Add optional external_id field to AWS SD ECS/MSK/RDS/Elasticache
- **added** — Allow EC2 service discovery to discover IPv6 addresses to communicate with target endpoints
- **added** — Add --header flag to promtool query instant command
- **changed** — Emit warning when sort, sort_by_label or sort_by_label_desc is used within range (matrix) queries
- **fixed** — Fix info() function incorrectly handling negated __name__ matchers
- **fixed** — Fix smoothed rate/increase returning zero instead of no result when all data falls strictly after the query range

This release contains security fixes, new features (especially around PromQL and Service Discovery), performance improvements in TSDB, Start Timestamp improvements and numerous bug fixes.

Thanks to all contributors!

##### Key Highlights
*   **Security**: Two security vulnerabilities have been addressed: a denial of service in remote-write (snappy decompression limit) and a secret exposure leak in STACKIT service discovery.
*   **PromQL & Metadata**: Several features and bug fixes related to the experimental "start timestamps" support, including updates to `rate()`, `irate()`, `increase()`, and `resets()`. New experimental functions `start()`, `end()`, `range()`, and `step()` are introduced.
*   **TSDB Performance**: Optimizations in head chunk lookup (constant time) and mmap operations to reduce CPU usage.
*   **Service Discovery**: Added support for DigitalOcean Managed Databases and Outscale VM, along with improvements to AWS SD (IPv6 support for EC2, external ID support).
*   **UI**: Added a web interface for deleting time series and cleaning tombstones.

##### Changelog

- [SECURITY] Remote: Reject snappy-compressed received requests via Remote Write whose declared decoded length exceeds the 32MB. Thanks to @hibrian827 for reporting it. #18642
- [SECURITY] STACKIT SD: Fix secrets being exposed in plaintext via `/-/config` endpoint. Thanks to @August829 and @Phaxma for reporting. GHSA-39j6-789q-qxvh #18649
- [CHANGE] TSDB/Agent: Adds Start Timestamp field to all WAL Histogram samples in memory; used `st-storage` flag is enabled. #18221
- [FEATURE] API: Add `/api/v1/status/self_metrics` endpoint returning the current state of the Prometheus server's own metrics about itself as JSON. #18411
- [FEATURE] Discovery: Add DigitalOcean Managed Databases service discovery #18287
- [FEATURE] Prometheus: Add support for the aix/ppc64 compilation target #18321
- [FEATURE] Discovery: Add Outscale VM service discovery (`outscale_sd_configs`) for discovering scrape targets from the Outscale Cloud API. #18139
- [FEATURE] PromQL: Emit a warning when `sort`, `sort_by_label` or `sort_by_label_desc` is used within range (matrix) queries, as these functions do not have effect in that context. #18498
- [FEATURE] PromQL: Add `start()`, `end()`, `range()`, and `step()` experimental functions #17877
- [FEATURE] PromQL: Update `resets()` function to consider start timestamp resets. Hidden behind `use-start-timestamps` feature flag. #18627
- [FEATURE] Prometheus: Promote auto-reload-config as stable #18620
- [FEATURE] TSDB/Agent: Add `CheckpointFromInMemorySeries` option to `agent.DB` that enables checkpoint based on in-memory series. #17948
- [FEATURE] UI: Add a web interface for deleting time series and cleaning tombstones, accessible from the Status menu. #18390
- [FEATURE] PromQL: Use start timestamps for `rate()`, `irate()`, and `increase()` calculations, behind a feature flag `use-start-timestamps`. Doesn't work together with extended range selectors `anchored` and `smoothed`. #18344
- [FEATURE] Scrape: Added a feature flag `st-synthesis` which synthesizes unknown STs for scraped cumulative metrics. Useful when Remote Writing 2.0 with delta or Otel-based backends. #18279
- [FEATURE] promqltest: support `@st` annotation in `load` blocks to specify per-sample start timestamps. #18360
- [ENHANCEMENT] API: reject concurrent fgprof profiles. #18651
- [ENHANCEMENT] AWS SD: Add optional `external_id` field to ECS/MSK/RDS/Elasticache. #18579
- [ENHANCEMENT] AWS SD: Add optional `external_id` field. #17171
- [ENHANCEMENT] Discovery: Propagate SD target updates faster by introducing dynamic backoff interval instead of static 5s interval for throttling. #18187
- [ENHANCEMENT] Promtool: Add `--header` flag to `query instant` command, matching existing `query range` behaviour. #18418
- [ENHANCEMENT]: AWS SD: Allows EC2 service discovery to discover IPv6 addresses to communicate with target endpoints. The private IPv4 addr

_[Truncated at 4000 characters — full notes: https://github.com/prometheus/prometheus/releases/tag/v3.12.0-rc.0]_

### v3.11.3 — 3.11.3 / 2026-04-27

- Date: 2026-04-27
- Version: v3.11.3
- Original notes: https://github.com/prometheus/prometheus/releases/tag/v3.11.3
- Permalink: https://whatsnew.fyi/product/prometheus/releases/v3.11.3

- **security** — Fix OAuth client_secret being exposed in plaintext via /-/config endpoint in AzureAD remote write
- **security** — Reject snappy-compressed requests in remote-read whose declared decoded length exceeds the decode limit
- **security** — Fix stored XSS via unescaped le label values in old UI heatmap chart tick labels

This release fixes mutiple security issues.

We would like to thank the following people for the responsible disclosures:
- Shadowbyte (4c1dr3aper) - Charlie Lewis for the Remote-Read snappy decode vulnerability.
- Brett Gervasoni for the AzureAD OAuth `client_secret` vulnerability.
- @iiihaiii and @Ngocnn97 for the Old UI XSS vulnerability. 

- [SECURITY] AzureAD remote write: Fix OAuth `client_secret` being exposed in plaintext via `/-/config` endpoint. GHSA-wg65-39gg-5wfj / CVE-2026-42151 #18590
- [SECURITY] Remote-read: Reject snappy-compressed requests whose declared decoded length exceeds the decode limit. GHSA-8rm2-7qqf-34qm / CVE-2026-42154 #18584
- [SECURITY] UI: Fix stored XSS via unescaped `le` label values in old UI heatmap chart tick labels. GHSA-fw8g-cg8f-9j28 #18588