# Tesseract.js changelog

> OCR in the browser and Node, as a WebAssembly port of Tesseract.

- Vendor: naptha
- Category: AI
- Official site: https://tesseract.projectnaptha.com
- Tracked by: What's New (https://whatsnew.fyi/product/tesseract-js)
- Harvested from: GitHub (naptha/tesseract.js)
- 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.

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

### v7.0.0

- Date: 2025-12-15
- Version: v7.0.0
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v7.0.0
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v7.0.0

- **added** — A new relaxedsimd build that takes advantage of the latest WASM and hardware capabilities
- **changed** — Significant improvements to recognition speed, with runtimes reduced by approximately 15-35% depending on device and use-case
- **removed** — Dropped support for Node.js v14

##### What's Changed
* Significant improvements to recognition speed (by @fanchenkong1 in https://github.com/naptha/tesseract.js/pull/1039)
   * A new `relaxedsimd` build takes advantage of the latest WASM and hardware capabilities.
   * Upgrading from v6 to v7 reduces runtimes by ~15-35% (depending on device and use-case).  The highest uplifts are currently seen on the latest Intel processors.
* Dropped support for Node.js v14.
* Various minor changes


##### New Contributors
* @hata6502 made their first contribution in https://github.com/naptha/tesseract.js/pull/1035
* @fanchenkong1 made their first contribution in https://github.com/naptha/tesseract.js/pull/1039

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v6.0.1...v7.0.0

### v6.0.1

- Date: 2025-04-07
- Version: v6.0.1
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v6.0.1
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v6.0.1

- **changed** — Switched from using node-fetch to using built-in fetch implementation for Node.js v18 and newer
- **fixed** — Resolve dependency-related warning message

##### What's Changed
* Switched from using `node-fetch` to using built-in `fetch` implementation for Node.js v18 and newer.
   - This resolves a nuisance dependency-related warning message reported in #876
* Various minor updates

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v6.0.0...v6.0.1

### v6.0.0

- Date: 2025-01-07
- Version: v6.0.0
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v6.0.0
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v6.0.0

- **fixed** — Fixed memory leaks that caused memory to rise over time and eventually lead to crashes
- **changed** — Reduced runtime and memory usage for most users by updating default formats
- **fixed** — Fixed compatibility with Electron main process
- **fixed** — Fixed bug where user-provided parameters were overwritten by defaults
- **changed** — All output formats other than text are now disabled by default
- **changed** — The JavaScript object output format (blocks) now returns only the array of blocks instead of automatically generating lists of words and symbols
- **changed** — Only text-based blocks are reported, non-text blocks are no longer automatically reported
- **changed** — The shape of some block objects was changed, with main properties text and bbox remaining unchanged
- **removed** — Removed previously deprecated functions including worker.initialize and worker.loadLanguage

##### What's Changed
- Fixed memory leaks (#977)
   - This version fixed a long-standing issue where memory would rise over time, eventually leading to a crash.
- Reduced runtime and memory usage for most users by updating default formats (#916).
- Fixed compatibility with Electron main process (#925)
- Fixed bug where user-provided parameters were overwritten by defaults (#975).

###### Breaking Changes
1. All outputs formats other than `text` are now disabled by default.
   - To re-enable the `hocr` output (for example), set the following: `worker.recognize(image, {}, { hocr: true })`
      - See [here](https://github.com/naptha/tesseract.js/blob/c75a380171e2df87e045808cbc16359a6959f08f/src/index.d.ts#L75-L89) for a list of possible output formats.
1. The JavaScript object output format (`blocks`) was tweaked.
   - Only the array of blocks (`blocks`) is returned.
      - Previous versions would automatically generate lists of every unit of text (`words`, `symbols`, etc.).
         - If needed, these should now be generated by the user.
   - Only text-based blocks are reported.
      - Previous versions reported non-text blocks when detected by Tesseract (e.g. line segments).
   - The shape of some objects were changed.
      - See the [type declarations](https://github.com/naptha/tesseract.js/blob/master/src/index.d.ts) for reference on properties.
      - The main properties--`text` and `bbox`--are unchanged.
1. Various functions and options marked as depreciated previously have been removed.
   1. This includes `worker.initialize` and `worker.loadLanguage`, along with several depreciated options from v2.

See #993 for additional discussion about this release.

##### New Contributors
* @IgorAufricht made their first contribution in https://github.com/naptha/tesseract.js/pull/971

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.1.1...v6.0.0

### v5.1.1

- Date: 2024-08-24
- Version: v5.1.1
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.1.1
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.1.1

- **fixed** — Bug where incorrect language data was loaded when oem is 2
- **fixed** — Bug where boolean values in blocks output format would always be false

##### What's Changed
* Fixed bug where incorrect language data was loaded when `oem` is `2` (#938)
* Fixed bug where boolean values in `blocks` output format would always be `false` (#907)

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.1.0...v5.1.1

### v5.1.0

- Date: 2024-05-07
- Version: v5.1.0
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.1.0
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.1.0

- **added** — Add line size metrics to blocks output including rowAttributes property with ascenders, descenders, and row_height metrics on line objects

##### What's Changed
* Added line size metrics to `blocks` output (#906)
   * `line` objects now include a property named `rowAttributes`, which is an object containing `ascenders`, `descenders`, and `row_height` metrics
   * These metrics allow for manual font size calculations that are more accurate than using the `font_size` property.
* Updates to documentation, types, and dependencies

##### New Contributors
* @Kishlay-notabot made their first contribution in https://github.com/naptha/tesseract.js/pull/896
* @k-nero made their first contribution in https://github.com/naptha/tesseract.js/pull/922

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.0.5...v5.1.0

### v5.0.5

- Date: 2024-02-26
- Version: v5.0.5
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.5
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.5

- **fixed** — Fixed bug triggered by running worker.recognize while a previous call to worker.recognize is still running
- **fixed** — Fixed bug with rotateAuto option unnecessarily inflating runtime
- **changed** — Minor fixes to documentation and types

##### What's Changed
* Fixed bug triggered by running `worker.recognize` while a previous call to `worker.recognize` is still running (#875) 
   * Sending multiple jobs to the same worker at the same time is still not recommended.
   * Instead, [schedulers](https://github.com/naptha/tesseract.js/blob/master/docs/workers_vs_schedulers.md) should be used to coordinate running jobs in parallel (see [this example](https://github.com/naptha/tesseract.js/blob/master/examples/browser/basic-scheduler.html))
* Fixed bug with `rotateAuto` option unnecessarily inflating runtime (#892)
* Minor fixes to documentation and types

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.0.4...v5.0.5

### v5.0.4

- Date: 2023-12-24
- Version: v5.0.4
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.4
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.4

- **fixed** — Support for setting "init only" parameters using the config option of createWorker, such as load_number_dawg

##### What's Changed
* Fixed support for setting "init only" parameters using `config` option of `createWorker` (#862)
   - For example, `load_number_dawg` is an "init only" parameter that cannot be set using either `worker.setParameters` or the `options` argument of `worker.recognize`.
   - However, `load_number_dawg` can be set by the following `createWorker` statement. 
      -  `createWorker('eng', "0", {}, {load_number_dawg: "0"});`
* Improvements to documentation 

##### New Contributors
* @rnwst made their first contribution in https://github.com/naptha/tesseract.js/pull/852

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.0.3...v5.0.4

### v5.0.3

- Date: 2023-10-30
- Version: v5.0.3
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.3
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.3

- **changed** — Minor changes to types, documentation, and build

##### What's Changed
* Minor changes to types, documentation, and build

##### New Contributors
* @dora-micha made their first contribution in https://github.com/naptha/tesseract.js/pull/843

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.0.2...v5.0.3

### v5.0.2

- Date: 2023-10-03
- Version: v5.0.2
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.2
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.2

- **fixed** — Fixed bugs with wrong lang data being loaded

##### What's Changed
* Fixed bugs with wrong lang data being loaded per #834 and #835 by @Balearica in https://github.com/naptha/tesseract.js/pull/836

Version `5.0.1` is nearly identical to `5.0.2` and was the latest version for under a day, so does not have its own release notes. 

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v5.0.0...v5.0.2

### v5.0.0

- Date: 2023-09-28
- Version: v5.0.0
- Original notes: https://github.com/naptha/tesseract.js/releases/tag/v5.0.0
- Permalink: https://whatsnew.fyi/product/tesseract-js/releases/v5.0.0

- **changed** — File sizes reduced by 54% for English and 73% for Chinese
- **changed** — Worker memory utilization reduced from 311 MB to 164 MB (47% reduction)
- **fixed** — Made compatible with iOS 17
- **changed** — Language and OEM arguments now set in createWorker instead of loadLanguage and initialize
- **changed** — worker.initialize and worker.loadLanguage functions now do nothing
- **added** — worker.reinitialize function to reinitialize workers with different settings
- **changed** — corePath directory must now contain all 4 core files (tesseract-core.wasm.js, tesseract-core-simd.wasm.js, tesseract-core-lstm.wasm.js, tesseract-core-simd-lstm.wasm.js)
- **changed** — worker.detect function disabled by default, requiring legacyCore and legacyLang options to enable
- **changed** — Language data loaded from jsdelivr by default instead of GitHub pages
- **removed** — Separate development build that produced tesseract.dev.js and worker.dev.js

##### What's Changed

##### Major New Features
1. **Significantly** smaller file sizes
   1. 54% smaller file sizes for English, 73% smaller for Chinese (see #806 for details)
   2. This results in a **~50% decrease** in runtime for first-time users (who do not yet have the data downloaded/cached)
1. Significantly lower memory usage
   1. Worker memory utilization in the [web benchmark](https://github.com/naptha/tesseract.js/blob/dev/v5/benchmarks/browser/speed-benchmark.html) is reduced from 311 MB to 164 MB (47% reduction)
   2. The lower memory footprint makes it feasible to use more workers, significantly improving performance for projects that utilize [schedulers](https://github.com/naptha/tesseract.js/blob/master/docs/intro.md) for parallel processing
1. Compatible with iOS 17 (using default settings)
   1. iOS 17 broke compatibility with Tesseract.js v4--upgrading to v5 should resolve
      1. See discussion section below for details

##### Breaking Changes Impacting Many Users
1. `createWorker` arguments changed
   1. Setting non-default language and OEM now happens in `createWorker`
      1. E.g. `createWorker("chi_sim", 1)`
1. `worker.initialize` and `worker.loadLanguage` functions now do nothing and can be deleted from code
   1. Loading the language and initialization now occurs in `createWorker`
   4. Workers can be re-initialized with different settings using `worker.reinitialize`

In other words, code should be modified from this:

```
const worker = await Tesseract.createWorker();
await worker.loadLanguage('eng');
await worker.initialize('eng');
const ret = await worker.recognize(file);
```
To this:

```
const worker = await Tesseract.createWorker("eng");
const ret = await worker.recognize(file);
```


##### Breaking Changes Impacting Fewer Users
1. Users who manually set `corePath` will need to update the contents of their `corePath` directory
   1. `corePath` should point to a directory that contains **all 4** of the files below from Tesseract.js-core v5:
      1. `tesseract-core.wasm.js`
      2. `tesseract-core-simd.wasm.js`
      3. `tesseract-core-lstm.wasm.js`
      4. `tesseract-core-simd-lstm.wasm.js`
   1. Tesseract.js will automatically select the correct version to use 
1. `worker.detect` function disabled by default
   1. Orientation + script detection is a function of the Legacy model only, which is no longer included by default
   6. To enable, set arguments  `legacyCore: true` and `legacyLang: true` in `createWorker` options
      1. E.g. `Tesseract.createWorker("eng", 1, {legacyCore: true, legacyLang: true});`
1. Language of progress logs standardized
   1. This should only impact users who parse status logs (e.g. to update a loading bar)

##### Non-Breaking Changes
1. Language data loaded from `jsdelivr` by default (rather than GitHub pages)
   1. This should result in improved performance and uptime
1. Separate "development" build (that produced `tesseract.dev.js` and `worker.dev.js` removed
1. Documentation and examples were modified to prevent new users from using `Tesseract.recognize` and `Tesseract.detect`
   1. Users who already use these functions are encouraged to modify their code to use `worker.recognize` and `worker.detect` instead

Considering upgrading from v2 to v5?  See #771 for a full guide for updating. 

**Full Changelog**: https://github.com/naptha/tesseract.js/compare/v4.1.3...v5.0.0