We’ve just released EmEditor v25.4.2. This update delivers several important fixes and optimizations to keep your experience smooth and stable, so we recommend updating as soon as possible.

• Added support for GPT-5.1 (the ChatAI plug-in is required).
• Fixed occasional malfunctions in AI prompts (the ChatAI plug-in is required).
• Fixed an issue that sometimes caused the status bar’s line/column display to be cut off.
• Fixed a problem in the Large File Controller when using case-insensitive regular-expression filters.
• Fixed an issue where the Keyboard page in settings could show an asterisk—as if it had been modified—even when the defaults were unchanged.
• Fixed unexpected behavior triggered by double-clicking [+] in tree views like the Snippets and CommitList plug-ins.
• Fixed a crash that could occur in the CommitList plug-in when double-clicking a directory in the Commit List pane after comparing commits.
• Fixed a bug where undo could stop working after making a few box selections under low-memory conditions.
• Adjusted the position of the balloon notification when opening EmEditor with a very large file.
• Fixed an issue that made Find in Files extremely slow when symbolic links or junctions were involved.
• Improved performance across multiple areas, including file opening, Find in Files, and horizontal scrolling on very long lines.

If you use the Desktop Installer version, you can select Check for Updates from the Help menu to download the latest version. If this method fails, please download the latest version, and run the downloaded installer. If you use the Desktop portable version, you can go to the Download page to get the latest version. The Store App version can be updated through the (Microsoft Store after a few days.

We’ve released EmEditor v25.4.0.

This update focuses first and foremost on speed. We optimized numerous parts of the code so that many actions now run faster, especially on CPUs that support AVX‑512. I used the Chat with AI feature to help write the new optimizations; it felt like having another excellent engineer at my side.

We also made classic, non‑AI optimizations. Find, Replace, Find in Files, and Replace in Files have been reworked to process UTF‑8 directly whenever possible, avoiding round trips to UTF‑16. Previously, Replace in Files on UTF‑8 converted to UTF‑16 and back; now replacements can happen directly on UTF‑8, eliminating conversion overhead. We also added a new Find in Files option: “Display File Names, Lines, and Matched Lines (truncate long lines),” enabled by default. Even when targets include very long lines (such as binaries), EmEditor now truncates output instead of printing entire lines for stable, responsive results. In our tests, Find, Replace, Find in Files, and Replace in Files were between about 2x and 6.5x faster.

Stability has also improved. Find in Files runs multithreaded, but searching many huge files at once could use a lot of memory. We now limit the number of threads that open very large files to reduce memory usage. If memory allocation fails, EmEditor automatically falls back to a lower‑memory, single‑threaded mode and retries the operation, lowering the chance of a crash.

After discontinuing the HTMLBar plug‑in in v25.3, some users missed the quick tag‑insertion buttons. In this release, you can define snippets directly in EmEditor and invoke them from menus, toolbars, or keyboard shortcuts. Execution is still handled by the Snippets plug‑in. To show the Snippets toolbar, go to View > Toolbars > Snippets. Create a snippet by dragging any text onto the Snippets toolbar, or define snippets via Customize > Snippets. For syntax details, see “To Use the Snippets Plug‑in” in the Help, or ask an AI for “EmEditor snippet syntax”.

Chat with AI (by Makoto Emura) has also received upgrades:

• New Web Search option for certain models (such as GPT‑5) to retrieve current information (for example, train timetables).
• New Text Verbosity control to adjust response length.
• Option to use environment variables (for example, OPENAI_API_KEY).
• Backend optimizations for better performance.

Note: To use AI features, including Chat with AI, install the ChatAI plug‑in separately.

We also fixed issues found during the preview build.

We hope both the Pro and Free editions meet your expectations. If you have questions, feature requests, or ideas, please contact us or post on the forum.

We appreciate your continued support of EmEditor.
— Yutaka Emura

For details, including major changes and screenshots, see “What’s New in Version 25.4.”

If you use the Desktop Installer edition, update from Help > Check for Updates. If that doesn’t work, download the latest version (https://support.emeditor.com/en/downloads/suggested) and run the installer. The Desktop Portable edition can be downloaded and updated here. The Store App edition will be available for download or update from the Microsoft Store in a few days.

We released EmEditor v25.3.0 today.

Generative AI Enhancements (ChatAI plugin required)

One of the biggest additions in v25.3 is enhanced generative AI support, developed by Makoto Emura. This release adds Google as a provider and supports OpenAI’s GPT‑5. EmEditor now also supports Tool Calling, which lets the AI invoke a limited set of built-in EmEditor tools. It’s similar to an AI agent, but restricted to tools that EmEditor exposes—hence the name “Tool Calling.” With this, you can run natural-language commands on the currently open document via the Chat with AI interface. For example, if you open a file with email addresses and type “Extract email addresses from this document” into the Chat with AI bar, EmEditor will extract them and create a new document.

To use Tool Calling, click the “Tools” button and ensure it’s highlighted in blue. You can also choose which tools are enabled on the Tool Calling page in Chat with AI settings.

The Chat with AI Settings and the AI Options page in the Customization dialog let you set Max tokens and Temperature (randomness). Previously, the default Max tokens was 4096, which could cause truncated output for reasoning-heavy models like GPT‑5. In this version, you can toggle Max tokens on or off. When it’s off, the provider’s default is used.

In Chat with AI Settings, you can also adjust Reasoning effort where supported. When Reasoning effort is off, the model’s default is used. Higher effort yields more reliable responses but can be slower. If you want the fastest replies, turn Reasoning effort on and select Minimal.

Sort by Similarity

EmEditor includes many sorting commands, and this version adds the ability to sort by similarity to the text on the current line or in the current cell. Similarity is calculated using the Levenshtein distance (edit distance) introduced in v22.0.0, with an option to ignore case. For example, if you have a CSV roster and search for Michael, placing the cursor on Michael and running Sort by Similarity will sort the list so close matches like Micheal and Mike appear first—making similar names easier to spot.

Markdown/HTML Toolbar

We’ve added HTML features to the Markdown toolbar introduced in v24.4 and combined them into a single Markdown/HTML toolbar. Markdown and HTML modes switch automatically. Opening a Markdown file and choosing Markdown settings or turning on Markdown Design Mode enables Markdown mode; opening an HTML file and choosing HTML settings enables HTML mode. Accordingly, the old HTMLBar plugin has been discontinued. The new HTML mode is more capable than HTMLBar. For example, the drop-down for Paragraph, Heading 1, Heading 2, and more automatically detects and shows the current style, and buttons like Bold, Italic, and Code reflect the current font state. If no text is selected and you click Bold, the word at the cursor becomes bold. Selecting the Bold command (Ctrl+B by default) while selecting text produces **text** in Markdown mode and <strong>text</strong> in HTML mode.

Performance and More

We continued optimizing startup performance in this release. The Extract Frequent Strings command is also significantly faster. In our tests, startup is 1.90× faster than v25.0, and Extract Frequent Strings is 1.42–4.44× faster than v25.2.

Other improvements include:

• Responding to a customer request, you can now add conditions to regex highlight strings with special keywords like (?#_text_c!=17) for more flexible highlighting.
• Extract Frequent Strings now respects filters and works on filtered content.
• Previously, the cursor position didn’t change after sorting. Now it moves to the corresponding item, making it easier to run the new Sort by Similarity followed by additional sorts within Advanced Sort.
• In addition to the Customize dialog, the Customize Macros dialog and Configuration Properties now show an asterisk (*) next to page titles that differ from default settings.

We also fixed issues found during the preview build. Starting with this version, the trial period before registration changes from 30 days to 7 days.

We hope both the Pro and Free editions meet your expectations. If you have questions, feature requests, or ideas, please contact us or post on the forum.

We appreciate your continued support of EmEditor.
— Yutaka Emura

For details, including major changes and screenshots, see “What’s New in Version 25.3.” (/text-editor-features/history/new-in-version-25-3/)

If you use the Desktop Installer edition, update from Help > Check for Updates. If that doesn’t work, download the latest version (https://support.emeditor.com/en/downloads/suggested) and run the installer. The Desktop Portable edition can be downloaded and updated here. The Store App edition will be available for download or update from the Microsoft Store in a few days.