# RxJava changelog

> RxJava release notes.

- Vendor: RxJava
- Category: Languages & Runtimes
- Official site: https://dsc.gg/rxjava
- Tracked by: What's New (https://whatsnew.fyi/product/rxjava)
- Harvested from: GitHub (ReactiveX/RxJava)
- Entries below: 10 (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.

## Releases

### v4.0.0-alpha-20

- Date: 2026-07-21
- Version: v4.0.0-alpha-20
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-20
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-20

- **added** — Streamable operator with blockingLast, ignoreElements, repeat, repeatWhen, retry, and retryWhen support
- **changed** — Optimized range and collect internals with improved Streamable implementation
- **changed** — Optimized several operator internals for Streamable
- **changed** — Optimized mapOptional operator performance
- **changed** — Optimized filter, map fusion, and lastOrError for Streamable
- **changed** — Optimized skip operations for Streamable
- **changed** — Optimized flattenAsFlowable with deferred evaluation
- **changed** — Optimized collect slow path and concatIterable
- **changed** — Reduced whenComplete usage in collect operation

##### What's Changed

###### Implementation

* 4.x: Streamable + blockingLast + ignoreElements by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8231
* 4.x: Streamable + repeat, repeatWhen, retry, retryWhen by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8232
* 4.x: Streamable, improved range and collect internals + JMH by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8235
* 4.x: Streamable - optimize several operator internals by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8238
* 4.x: Streamable Operator optimizations 7/18 by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8239
* 4.x: Streamable mapOptional +perf by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8240

###### Dependabot
* chore(deps): bump jupiterLauncherVersion from 6.1.1 to 6.1.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8233
* chore(deps): bump org.junit.jupiter:junit-jupiter from 6.1.1 to 6.1.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8234
* chore(deps): bump github/codeql-action/upload-sarif from 4.37.0 to 4.37.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8236
* chore(deps): bump actions/setup-java from 5.5.0 to 5.6.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8237
* chore(deps): bump actions/setup-python from 6.3.0 to 7.0.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8241
* chore(deps): bump actions/checkout from 7.0.0 to 7.0.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8242

###### Streamable Scrabble

[Ongoing measure/optimization](https://github.com/akarnokd/akarnokd-misc/blob/master/src/jmh/java/hu/akarnokd/comparison/scrabble/ShakespearePlaysScrabbleWithRxJava4StreamableOpt.java). Managed to shave over half the time off (but some came from using better collector implementations for sure).

:computer: i9 275HX, 32GB LPDDR5 6400MT CL52, Windows 25H2, JDK 26.0.1

| Step | Time (ms) | Improvement | vs Baseline |
|------|------|-------------:|-------------:|
| Baseline | 42,5119 | - | - |
| Avoid `whenComplete` usage in `collect` | 37,566 | -11,65% | - |
| IndexableSource in `collect` | 35,815 | -4,66% | -15,77% |
| concatIterable optimizations | 31,971 | -10,73%  | -24,81% |
| map fusions | 30,623 | -4,22% | -27,98% |
| flattenAsFlowable deferred opt | 27,999 | -8,57%  | -34,15% |
| MutableLong in the bench | 26,159 | -6,57% | -38,48% |
| lastOrError opt | 25,164 | -3,80% | -40,82% |
| custom  `Collector` summers | 24,885 | -1,11% | -41,47% |
| skip optimizations | 24,791  | -0,38% | -41,69% |
| filter opt, filter+map fusion, lastOrError opt | 23,566 |  -4,94% | -44,58% |
| slow path collect optimization  |  22,392 | -4,98% | -47,34% |
| CharStreamer EnumerableSource marker | 21,843 | -2,45% | -48,63% |
| custom max collector |  20,369 | -6,75% | -52,09% |

Versus the other techs
|Tech | Time in milliseconds |
|-- | --:|
|For Loop JDK 26 | 2,125|
|IObservable synchronous | 7,917|
|IEnumerable port | 8,225|
|Ix 1.0.0 | 8,463|
|RxJava Observable 3.1.12 | 10,119|
|**RxJava Observable 4a19** :arrow_backward: | **10,484**|
|RxJava Observable 2.2.21 | 10,612|
|RxJava Flowable 4a19 | 11,424|
|RxJava Flowable 3.1.12 | 12,499|
|RxJava Flowable 2.2.21 | 13,849|
|Reactive4Java 0.98.1 | 13,086|
|Guava 33.6.0 | 12,564|
|Reactor 3.8.6 | 14,158|
|CyclopsReactOpt | 17,273|
|:new: RxJava Streamable 4a20  :arrow_backward: | 20,369 |
|JOOL 0.9.15 | 38,876|
|RxJava Streamable 4a19  :arrow_backward: | 42,512 |

<!--EndFragment-->
</body>
</html>

**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-19...v4.0.0-alpha-20

### v4.0.0-alpha-19

- Date: 2026-07-11
- Version: v4.0.0-alpha-19
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-19
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-19

- **added** — Add Streamable.concat, using, and test fixes
- **changed** — Replace Streamable.stream() DisposableContainer with StreamerCancellation
- **changed** — Separate streamer cancellation from DisposableContainer in Streamable
- **added** — Add native take implementation for Streamable
- **added** — Add Streamable.blockingFirst, blockingLast, blockingLastOrError, skip, and Single.flattenAsStreamable methods

#### What's Changed

##### API
* 4.x: Streamable + concat, using, test fixes by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8220
* 4.x: Streamable.stream() DisposableContainer -> StreamerCancellation by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8221
* 4.x: Streamable ~ separate streamer cancellation & DisposableContainer by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8223
* 4.x: Streamable ~ take native implementation by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8226
https://github.com/ReactiveX/RxJava/pull/8228
* 4.x: Streamable + blockingFirst, last[OrError], skip, Single.flattenAsStreamable by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8229

##### Dependabot
* chore(deps): bump actions/setup-java from 5.4.0 to 5.5.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8222
* chore(deps): bump github/codeql-action/upload-sarif from 4.36.3 to 4.37.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8225
* chore(deps): bump trufflesecurity/trufflehog from 3.95.8 to 3.95.9 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8230

##### Misc

* Add Streamable class to README base classes section by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8224
* 4.x: Update Readme with some small changes to trigger the beauty scanner by @akarnokd in 
* 4.x: Fix entropy-beauty-scan wrong diff issue, via Grok by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8227

**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-18...v4.0.0-alpha-19

### v4.0.0-alpha-18

- Date: 2026-07-07
- Version: v4.0.0-alpha-18
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-18
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-18

- **added** — Streamable API with range, fromArray, take, error, defer operators
- **added** — Streamable API with fromIterable, fromStream, hide, never operators
- **added** — Streamable API with map, filter, flatMap implementations
- **added** — Streamable operators doOnNext, intercept, lift, to
- **added** — Streamable API with timer and interval operators
- **added** — Streamable API with takeWhile, toObservable, and toStreamable conversion methods
- **added** — Streamable API with takeUntil and groupBy operators
- **added** — Streamable API with delay, timeout, zip, onErrorResumeNext operators
- **added** — DispatchStreamProcessor and other Streamable improvements
- **added** — Streamable operators doOnError and forEach(StreamSink)
- **changed** — Streamable and Streamer API redesign, dropping next and finish arguments
- **fixed** — SchedulerToExecutorService invokeAll and invokeAny implementation
- **changed** — Convert test suite from JUnit 4 to JUnit 6
- **removed** — Pioneer-RetryTest
- **added** — VirtualSchedulerTests extending AbstractSchedulerConcurrencyTests

##### API

* 4.x: Streamable + range, fromArray, take, error, defer by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8206
* 4.x: Streamable + fromIterable, fromStream, hide, never, fixes by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8207
* 4.x: Streamable + map, filter, flatMap impl, fixes and reworks by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8208
* 4.x: Streamable Ops: doOnNext, intercept, lift, to; test cleanup by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8209
* 4.x: Streamable/Streamer API rewamp, dropping next/finish args by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8212
* 4.x: Streamable + timer + interval; cleanups by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8213
* 4.x: Streamable + takeWhile, + fromXXX, + toObservable + ~.toStreamble by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8214
* 4.x: Streamable + takeUntil + groupBy + refactor + helpers by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8215
* 4.x: Streamable + delay, timeout, zip, onErrorResumeNext, cleanup by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8216
* 4.x: Streamable + DispatchStreamProcessor & other improvements by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8217
* 4.x: Streamable + doOnError, forEach(StreamSink) by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8218

##### Test

* 4.x: Add VirtualSchedulerTests extends AbstractSchedulerConcurrencyTests by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8204

##### Fixes

* 4.x: Fix SchedulerToExecutorService invokeAll and invokeAny impl by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8205

##### Cleanup

* 4.x: Convert from JUnit 4 to JUnit 6 by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8202
* 4.x: Remove Pioneer-RetryTest as it is itself flaky?! by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8203

##### Dependabot
* chore(deps): bump trufflesecurity/trufflehog from 3.95.6 to 3.95.7 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8201
* chore(deps): bump trufflesecurity/trufflehog from 3.95.7 to 3.95.8 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8210
* chore(deps): bump github/codeql-action/upload-sarif from 4.36.2 to 4.36.3 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8211

##### Documentation

* 4.x: What's different in 4.0 documentation, start by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8219


**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-17...v4.0.0-alpha-18

### v4.0.0-alpha-17

- Date: 2026-06-29
- Version: v4.0.0-alpha-17
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-17
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-17

- **changed** — Standardize config records into 3 main variants
- **removed** — Reduce Flowable API by removing concat*, merge, concatMap*, and flatMap* variants
- **removed** — Remove remaining Flowable operators and related APIs

##### What's Changed

###### API reductions

* 4.x: Standardize config records into 3 main variants by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8194
* 4.x: Flowable API reduction: concat*, merge, concatMap*, flatMap* by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8195
* 4.x: Flowable API reduction: remaining operators & other related changes by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8200

###### Dependabot

* chore(deps): bump jupiterLauncherVersion from 6.1.0 to 6.1.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8199
* chore(deps): bump actions/cache from 6.0.0 to 6.1.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8197
* chore(deps): bump jupiterVersion from 6.1.0 to 6.1.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8198


**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-16...v4.0.0-alpha-17

### v4.0.0-alpha-16

- Date: 2026-06-28
- Version: v4.0.0-alpha-16
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-16
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-16

- **removed** — Single.concat and Single.concatEager static methods
- **removed** — Single.merge static method
- **removed** — Maybe.concat, Maybe.concatEager, and Maybe.merge static methods
- **removed** — Observable.combineLatest static methods
- **removed** — Observable.concat static methods
- **removed** — Observable.merge static methods
- **removed** — Observable.concatEager static methods
- **removed** — Observable.sequenceEqual, Observable.switchOnNext, and Observable.zip static methods
- **removed** — Observable.concatArray, Observable.concatArrayEager, and related concat variants
- **removed** — Observable.flatMap*, Observable.groupBy, and Observable.observeOn overloads
- **removed** — Observable.switchMap static method
- **removed** — Disposable no longer implements AutoCloseable
- **fixed** — NullPointerException in AppendOnlyLinkedArrayList.forEachWhile on a full last chunk

##### What's Changed

###### API reductions
* 4.x: Single API reduction: concat & concatEager by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8167
* 4.x: Single API reduction: merge by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8168
* 4.x: Maybe API reduction: concat, concatEager, merge by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8169
* 4.x: Observable API reduction: combineLatest by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8172
* 4.x: Observable API reduction: concat by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8175
* 4.x: Observable API reduction: merge by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8176
* 4.x: Observable API reduction: concatEager by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8177
* 4.x: Observable API reduction: sequenceEqual, switchOnNext, zip by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8190
* 4.x: Observable API reduction: concat { Array, Eager, XYZ } by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8191
* 4.x: Observable API reduction: flatMap*, groupBy, observeOn by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8192
* 4.x: Observable API reduction: Observable.switchMap by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8193

###### Other API changes
* 4.x: Disposable no longer impls AutoCloseable by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8184

###### Cleanup

* 4.x: Cleanup + lambda instead of inner class check by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8179
* 4.x: Cleanup: Serial annotation, getFirst usage by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8180
* 4.x: Cleanup; build, safevarargs, small typos by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8183
* 4.x: Cleanup - Migration; lambdas expressions by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8188
* 4.x: Cleanup, fix inferable types via var or diamond by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8189
* 4.x: Cleanup, Java Migration; records, newer API, newer syntax by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8187
* 4.x: Cleanup: convert anonymous inner classes to lambdas in test files by @GautamKumarOffical in https://github.com/ReactiveX/RxJava/pull/8178
* 4.x: Cleanup, wording minor things by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8186


###### Bugfixes

* Fix NullPointerException in AppendOnlyLinkedArrayList.forEachWhile on a full last chunk by @vasiliy-mikhailov in https://github.com/ReactiveX/RxJava/pull/8174
  - Note on the contributor: Banned, AI Slop, Undisclosed AI Use, Had to Manually Correct PR
  - Contributing.md clearly states we (I) won't argue with your AI to fix the PR style or content or whatever.

###### Dependabot
* chore(deps): bump actions/setup-java from 5.3.0 to 5.4.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8182
* chore(deps): bump actions/cache from 5.0.5 to 6.0.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8170
* chore(deps): bump actions/setup-python from 6.2.0 to 6.3.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8171

##### New Contributors
* @GautamKumarOffical made their first contribution in https://github.com/ReactiveX/RxJava/pull/8178

**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-15...v4.0.0-alpha-16

### v4.0.0-alpha-15

- Date: 2026-06-23
- Version: v4.0.0-alpha-15
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-15
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-15

- **fixed** — Fix IllegalStateException in SchedulerToExecutorService.invokeAny
- **changed** — Turn Completable concatX and mergeX into config-based API

##### What's Changed

###### Fixes & Enhancements

* Fix IllegalStateException in SchedulerToExecutorService.invokeAny by @vasiliy-mikhailov in https://github.com/ReactiveX/RxJava/pull/8159
* 4.x: API turn Completable concatX and mergeX into config-based by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8166

###### Cleanup

* 4.x: Unit test lambdaification 14 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8155
* 4.x: Unit test lambdaification 15 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8156
* 4.x: Unit test lambdaification 16 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8157
* 4.x: Unit test lambdaification 17 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8158
* 4.x: Unit test lambdaification 18 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8160
* 4.x: Unit test lambdaification 19 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8161
* 4.x: Unit test lambdaification 20 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8162
* 4.x: Unit test lambdaification 21 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8163
* 4.x: Unit test lambdaification 22 of N by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8164
* 4.x: Unit test lambdaification 23 of 23 by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8165

###### Chores

None

**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-14...v4.0.0-alpha-15

### v4.0.0-alpha-14

- Date: 2026-06-22
- Version: v4.0.0-alpha-14
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-14
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-14

- **added** — Add task coordination primitives and implement a basic concat() operator
- **added** — Add +shared, +parallel, +blocking Scheduler
- **added** — Detect un-awaited CompletionStageDisposables during tests
- **fixed** — Fix Scheduler.toExecutorService() NullPointerException from null worker store
- **fixed** — Fix Scheduler.toExecutorService(boolean) logic
- **removed** — Remove Scheduler.when due to maintenance burden

##### What's Changed
* 4.x: Detect un-awaited CompletionStageDisposables during tests by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8093
* 4.x: Add task coordination primitives, implement a basic concat() operator by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8110
* Fix Scheduler.toExecutorService() NullPointerException from null worker store by @vasiliy-mikhailov in https://github.com/ReactiveX/RxJava/pull/8149
* 4.x: Scheduler.toExecutorService(boolean) logic fix by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8151
* 4.x: Remove Scheduler.when due to maintenance burden by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8153
* 4.x: +shared, +parallel, +blocking Scheduler by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8154

###### Chores
* chore(deps): bump gradle/actions from 6.0.1 to 6.1.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8095
* chore(deps): bump actions/github-script from 8 to 9 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8099
* chore(deps): bump trufflesecurity/trufflehog from 3.94.2 to 3.94.3 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8098
* chore(deps): bump SethCohen/github-releases-to-discord from 1.19.0 to 1.20.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8096
* chore(deps): bump actions/cache from 5.0.4 to 5.0.5 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8102
* chore(deps): bump com.google.guava:guava from 33.5.0-jre to 33.6.0-jre by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8103
* chore(deps): bump actions/upload-artifact from 7.0.0 to 7.0.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8101
* chore(deps): bump github/codeql-action from 4.35.1 to 4.35.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8104
* chore(deps): bump trufflesecurity/trufflehog from 3.94.3 to 3.95.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8105
* chore(deps): bump gradle-wrapper from 9.4.1 to 9.5.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8106
* chore(deps): bump github/codeql-action from 4.35.2 to 4.35.3 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8109
* chore(deps): bump github/codeql-action from 4.35.3 to 4.35.4 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8111
* chore(deps): bump gradle-wrapper from 9.5.0 to 9.5.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8113
* chore(deps): bump trufflesecurity/trufflehog from 3.95.2 to 3.95.3 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8112
* chore(deps): bump github/codeql-action from 4.35.4 to 4.35.5 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8114
* chore(deps): bump codecov/codecov-action from 6.0.0 to 6.0.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8115
* test: simplify SingleRetryTest callables by @puneetdixit200 in https://github.com/ReactiveX/RxJava/pull/8120
* chore(deps): bump github/codeql-action from 4.35.5 to 4.36.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8121
* chore(deps): bump biz.aQute.bnd.builder from 7.2.3 to 7.3.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8126
* chore(deps): bump trufflesecurity/trufflehog from 3.95.3 to 3.95.5 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8125
* chore(deps): bump actions/checkout from 6.0.2 to 6.0.3 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8124
* chore(deps): bump github/codeql-action from 4.36.0 to 4.36.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8123
* chore(deps): bump github/codeql-action from 4.36.1 to 4.36.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8127
* chore(deps): bump codecov/codecov-action from 6.0.1 to 7.0.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8129
* chore(deps): bump gra

_[Truncated at 4000 characters — full notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-14]_

### v4.0.0-alpha-13

- Date: 2026-04-03
- Version: v4.0.0-alpha-13
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-13
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-13

- **added** — Add optional build and test for future JDKs
- **changed** — Enhance Streamable/Streamer and DisposableContainer APIs
- **fixed** — Isolate windowUnsubscribeNonOverlappingAsyncSource to JUnit 5

##### What's Changed
* 4.x: Add optional build/test for future JDKs by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8077
* 4.x: Isolate FlowableMergeTest.synchronizationOfMultipleSequencesLoop by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8078
* chore(deps): bump codecov/codecov-action from 5.5.3 to 6.0.0 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8085
* Fix #8086: Isolate windowUnsubscribeNonOverlappingAsyncSource to JUnit 5 by @ZhangDT-sky in https://github.com/ReactiveX/RxJava/pull/8087
* chore(deps): bump github/codeql-action from 4.34.1 to 4.35.1 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8088
* chore(deps): bump trufflesecurity/trufflehog from 3.94.1 to 3.94.2 by @dependabot[bot] in https://github.com/ReactiveX/RxJava/pull/8091
* 4.x: Enhance Streamable/Streamer and DisposableContainer APIs by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8092

##### New Contributors
* @ZhangDT-sky made their first contribution in https://github.com/ReactiveX/RxJava/pull/8087

**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-11...v4.0.0-alpha-13

### v4.0.0-alpha-12

- Date: 2026-03-25
- Version: v4.0.0-alpha-12
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-12
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-12

- **added** — Add optional build and test support for future JDKs

##### What's Changed
* 4.x: Add optional build/test for future JDKs by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8077


**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-11...v4.0.0-alpha-12

### v4.0.0-alpha-11

- Date: 2026-03-25
- Version: v4.0.0-alpha-11
- Original notes: https://github.com/ReactiveX/RxJava/releases/tag/v4.0.0-alpha-11
- Permalink: https://whatsnew.fyi/product/rxjava/releases/v4.0.0-alpha-11

- **changed** — Upgrade to Java 26 baseline compilation

##### What's Changed
* 4.x: Upgrade to Java 26 baseline compilation, test isolation by @akarnokd in https://github.com/ReactiveX/RxJava/pull/8074


**Full Changelog**: https://github.com/ReactiveX/RxJava/compare/v4.0.0-alpha-10...v4.0.0-alpha-11