Version Numbering

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FPC, Lazarus combinations

Lazarus Release	Recommended FPC version	Notes
0.9.24 - 0.9.99	2.2.4
1.0.0 - 1.0.6	2.6.0
1.0.8 - 1.2.2	2.6.2
1.2.4 - 1.4.2	2.6.4
1.6.0 - 1.6.2	3.0.0	last version for Win98/ME using fpc 2.6.4
1.6.4	3.0.2
1.8.0 - 2.0.8	3.0.4
2.0.10	3.2.0
2.2.0 and newer	3.2.2

(See also: Free Pascal)

Explanation of the different version numbers of Lazarus

Internally, Lazarus version has the following structure:

Major.Minor.Release.Patch

The Lazarus release cycle

The Lazarus project has 2 kind of releases: Major and minor.

Major releases

Include new features.

Minor releases

Only bug fixes.

When a major release is made a new branch (git branch, earlier svn branch) is made from the "main" (aka "trunk" as it was called for svn) branch. The new branch will be called fixes_nn where "nn" is some numbering (see graph).

Development continues on the main branch. Selected bug-fixes are merged to the fixes branch. Minor releases are then made from the fixes branch.

In the past the the first 2 numbers (major.minor) where used for the major version, and the 3rd number (patch) indicated minor releases. There was no rule if a new major release would increase the major or minor number. It was therefore decided that major releases should always increase the major number. And minor releases should increase the minor number. The first major release with the new numbering is Lazarus 3.0

Lazarus 3.0 and newer

In Lazarus version 3.0 and up, the release number is always 0 (zero).
Major and minor version numbers are used to identify a release or a fixes branch.

An even minor version number, like x.0 or x.2, represents a general availability release.
An odd minor version number like x.1 or x.3 represents a fixes branch. For example: 3.1 would contain bug fixes for the 3.0 release and would be used as the basis for the 3.2 release.
Development (or trunk) versions are always represented as minor version number 99; i.e. 3.99 is the development branch for the future 4.0 release. Also, selected commits from this branch are cherry picked to the 3.x family.

Patch numbers identify a release candidate or a general availability release. For example: 3.0.0 RC1 has the the full version value of 3.0.0.1. RC2 has the value 3.0.0.2, and the released product could be 3.0.0.3.

Pre 3.0 versioning

In Lazarus preceding 3.0, versioning had the following differences:

Major, minor and release version numbers were used to identify a release or a fixes branch.
An even minor and release version numbers, like x.2.0 or x.2.2, represented a general availability release.
An odd minor version number indicated that it is a development (or trunk) version. Example: x.1.0.
An odd release version number indicated fixes branch. Example: 1.4.1 in Lazarus 1.4 series. 1.4.1 would have eventually become 1.4.2 general availability release.

How about fixed bugs, in which version is the fix included?

Take the issue [1] as an example.

It has a "milestone" set ("version 3.0").

• For open bugs the milestone indicates the currently planed target by witch the issue should be fixed. It may however be rescheduled.
• For closed issues, it is set to the release that will contain the issue.

Some issues also refer to the commit containing the fix. Usually the last "mentioned in commit" note. Or a dedicated comment by a developer. In this case [2]

On that commit page is the following info (needs to be unfolded)

   Branches containing this commit
   fixes_3_0 main
   Tags containing this commit
   lazarus_3_0_RC1 main_3_99 t-fixes-3

`lazarus_3_0_RC1` is the indicator that it will be in the 3.0 release (after the RC, in which it also is included)

Some older issues, that were imported from mantis have tags named "target". [3]

In the "mantis" block is the info "Fixed in revision" which links to a commit, as described above.

Version numbers in graph form

Maybe this will help some users understand the version numbering a bit better.

o - main branch becomes version 3.99: development + experimental stuff, fixes branch 3.0 is created
|
|\
| \
|  |
|  o - (branches\fixes_3_0) - feature freeze + release candidate
|  |\ 
|  | o - (tags\release_3_0_RC1)
|  |\ 
|  | o - (tags\release_3_0) - Release 3.0. After this release version in fixes branch is incremented to 3.1.
|  |\ 
|  | o - (tags\release_3_2) - Release 3.2. After this release version in fixes branch is incremented to 3.3.
|
o - main branch becomes version 4.99: development + experimental stuff, fixes branch 4.0 is created
|
|\
| \
|  |
|  o - (branches\fixes_4_0) - feature freeze + release candidate
|  |\ 
|  | o - (tags\release_4_0_RC1)
|  |\
|  | o - (tags\release_4_0) - this will happen in the future

Note that main branch gets a new version right after branching. So version 3.99 from main branch exists at the same time as version 3.x in fixes_3_0 branch.