X.Org Version Numbering Schemes
The XFree86 Project, Inc
Updated for X.Org by Keith Packard, Kevin E. Martin, and Alan Coopersmith
November 2010
X.Org has adopted the same basic numbering scheme used by the XFree86 Project,
Inc. for their releases. The actual numbers are different, but the basic scheme
is the same. This document reflects the policy that X.Org uses.
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Table of Contents
Module Versions
Releases, Development Streams, and Branches
Current Version Numbering Scheme
Development Branch
Stable Branch
Finding the X.Org X Server Version From a Client
Module Versions
Starting with the X11R7.0 release, each module has its own version number. For
those without a natural starting point, the version numbers started at 1.0. For
instance, the X11R7.0 release included the xorg-server 1.0 module. As modules
are released independently from the rest of the window system, the module
version is the most accurate source of version information. For instance, there
are many X server releases in a year, but generally only one window system
release, so an X server version number such as 1.7.7 is more informative than
the X11R7.5 version for the window system “katamari” release.
Unfortunately, up through the X server 1.3 release, the X server used the
Window System version when reporting its version number in log files, the
-version option, and the connection setup string (displayed by xdpyinfo). This
was corrected with X server 1.3, which caused the visible version number string
to appear to jump backwards from 7.2 to 1.3.
Releases, Development Streams, and Branches
X.Org has two release branches for the X server software, and several other
modules with active ongoing development. First is the trunk of the git
repository. This is the main development stream, where all new work and work
for future releases is done.
Second is the stable bugfix branch for the latest full release. It is created
around the time of the release. The branch will be named for the release
version, such as “server-1.9-branch” for the X server 1.9.x series of releases.
Fixes for bugs found in the release will be added to this branch (as well as
the trunk), and updates to this release (if any) will be cut from this branch.
Similar stable branches are present for previous full releases.
The X.Org Foundation is planning to make full releases from the main
development stream at regular intervals in the 6-12 month range. The feature
freezes for these releases will usually be 2-3 months before the release dates.
This general plan is a goal, not a binding commitment. The actual release
intervals and dates will depend to a large degree on the resource available to
X.Org. Update/bugfix releases will be made on an as-required basis, depending
also on the availability of resources, and will generally be limited to serious
bug and security fixes. New features will not usually be added in update
releases.
Aside from actual releases, snapshots of the active release branches are tagged
in the git repository from time to time. Each such snapshot has an identifiable
version number.
Current Version Numbering Scheme
Starting with the main development branch after X11R6.7, the X.Org versions are
numbered according to the scheme outlined here.
The version numbering format is M.m.P.s, where M is the major version number, m
is the minor version number, P is the patch level, and s is the snapshot
number. Full releases have P set to zero, and it is incremented for each
subsequent bug fix release on the post-release stable branch. The snapshot
number s is present only for between-release snapshots of the development and
stable branches.
Development Branch
Immediately after forming a release stable branch, the patch level number for
the main development branch is bumped to 99, and the snapshot number is reset.
The snapshot number is incremented for each tagged development snapshot. The
git tag for snapshots is “xorg-server-M.m.P.s”. When the development branch
enters feature freeze, the snapshot number is bumped to 900. A stable branch
may be created for the next full release at any time after the feature freeze.
When it is, the branch is called “server-M.m-branch”. The snapshot number is
incremented from there until the release is finalised. Each of these snapshots
is a “release candidate”. When the release is finalised, the minor version is
incremented, the patch level is set to zero, and the snapshot number removed.
Here's an example which shows the version number sequence for the development
leading up to version 1.8:
1.7.99.1 The first snapshot of the pre-1.8 development branch.
1.7.99.23 The twenty-third snapshot of the pre-1.8 development branch.
1.7.99.900 The start of the 1.8 feature freeze.
1.7.99.903 The third 1.8 release candidate.
1.8.0 The 1.8 release.
1.8.99.1 The first pre-1.9 development snapshot, which is the first main
branch snapshot after creating the 1.8 stable branch.
Stable Branch
After a full release, the stable branch for the release will be maintained with
bug fixes and important updates until the next full release. Any snapshots on
this branch are considered “release candidates,” which is indicated by setting
s to a number above 900. The snapshot number is incremented for each release
candidate until the update release is finalised. The patch level value (P) is
incremented for each update release.
Here's an example which shows a version number sequence for a 1.8.x stable
branch:
1.8.0 The 1.8 release.
1.8.0.901 The first pre 1.8.1 snapshot.
1.8.0.903 The third pre 1.8.1 snapshot, also known as the third 1.8.1 release
candidate.
1.8.1 The 1.8.1 release.
1.8.1.901 The first pre 1.8.2 snapshot.
1.8.2 The 1.8.2 release.
Finding the X.Org X Server Version From a Client
The X.Org X servers report a VendorRelease value that matches the X.Org version
number. There have been some cases of releases where this value wasn't set
correctly. The rules for interpreting this value as well as the known
exceptions are outlined here.
As noted above, the version reported by VendorRelease changed from the window
system version to the X server version starting in the xorg-server 1.3 release.
For all X.Org development and release versions using this numbering scheme, the
VendorRelease value is MMmmPPsss. That is, version M.m.P.s has VendorRelease
set to M * 10000000 + m * 100000 + P * 1000 + s.
The following is a code fragment taken from xdpyinfo.c that shows how the
VendorRelease information can be interpreted.
if (strstr(ServerVendor(dpy), "X.Org")) {
int vendrel = VendorRelease(dpy);
printf("X.Org version: ");
printf("%d.%d.%d", vendrel / 10000000,
(vendrel / 100000) % 100,
(vendrel / 1000) % 100);
if (vendrel % 1000) {
printf(".%d", vendrel % 1000);
}
}
