changelog

basicwidespread

A changelog is a chronological list maintained from software version to version, detailing what was newly added, what changed, and which bugs were fixed.

In plain terms

A changelog is like a car's service book: it lists by date what was replaced, fixed, or installed. It does not explain how the car works, but what happened to it over time.

It helps you avoid guessing what changed after an update. You can see whether new features arrived, whether something you used was discontinued, and whether security bugs were fixed.

This is particularly useful with AI tools because they change rapidly. A new version of a model or coding agent may behave differently than the old one, and in the best case, you learn of this change first from the changelog.

It differs from developers' internal notes in that it is meant for people: summarizing changes briefly, clearly, and highlighting key points.

How it works

Developers record what they changed while working: what is new, what was modified, what was fixed, and what was removed.
Upon release, these items are organized under a version number and a date, with the latest release at the top of the list.
Items are usually grouped, for example: new feature, modification, bug fix, security fix, removed feature.
The log is published: in a file named CHANGELOG alongside the program, on the product website, or in the "What's New" section of the app store.
An increasing number of first drafts are generated by machines: a coding agent writes the draft from saved modifications, which is then reviewed by a human.

An everyday example

Your banking app updates on your phone, and under "What's New" in the app store you read: "New: instant payment via QR code. Fixed: login error." These few lines constitute a short changelog.

Who is affected

developerThey write and read the most, because this shows whether an update could break their own program's operation. → Code

entrepreneur, executiveThis tells them whether a new version of the software or AI service used by the company affects daily operations.

employeeAfter updating workplace programs, you can see here what has moved and what can now be done differently. → Work & HR

everyoneYou encounter it with every app update, and it helps decide whether you should update immediately.

A common misconception

MythA changelog is just an incomprehensible technical list for programmers.

In realityA good changelog is written for people, concisely and clearly. The reader may be an ordinary user or a developer, so the language differs by product. A mechanical record that logs every minor detail is the developers' change history, which is a different genre.

Limits and risks

It is only as good as its careful management: many companies settle for 'bug fixes and performance improvements'.
Not complete: smaller or sensitive changes may be missing, so it is not proof that nothing else has changed.
With AI models, subtle shifts in behavior are hard to describe in a few lines, so alongside the logs, it is worth testing the new version yourself.
A machine-generated change log can be wrong or get lost in trivial details if no one reviews it.

Similar, but not the same

release notes – A release note typically concerns a single release, in a more detailed and explanatory tone, while the changelog is the continuous, concise history of all versions. In practice, the two terms are often used interchangeably.
commit log – The commit log mechanically records every small code modification for developers, while the changelog highlights only the changes important to the user from this.
documentation – Documentation describes how the program currently works, while a changelog details what has changed compared to the previous version.

Related concepts

Broader

software documentation, software development

Narrower

release notes

On the edge

version control, semantic versioning, commit, Git, coding agent, security patch

A brief history

Maintaining a changelog became a custom in the free software community; the GNU project coding standards describe it in a separate section. The most well-known, human-centric recommendation today, Keep a Changelog, was launched by Olivier Lacan in 2014.

Where things stand

By the end of 2026, most serious software and development tools keep a changelog, and the major AI providers also publish changes to their models and tools. The first draft is increasingly written by coding agents, while the final text is typically still approved by a human.

Status: 2026 November

In the news

Appears in 4 Agent Age stories; the curve shows weekly occurrence in the news magazine.

Harvey makes acquisition, announces partnership and launches new features for law firmsNov 2, 2026 · Jog
Amazon's Alexa for Shopping now buys, tracks prices and flags scamsSep 1, 2026 · Marketing
Claude Code now available with a self-hosted runner for Docker and GitHub ActionsAug 18, 2026 · Code
GitHub to deprecate Spark on github.comAug 4, 2026 · Code

Also known as

changelog · change log · CHANGELOG.md · changelog · change log · changelog · version history · new features

Sources

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.