[Development] QtCS2014 - Long-term releases

[Thiago Macieira]

We had an impromptu session on having a "Long term release" of Qt. There's 
some interest and we can gain a few things from it. We need to investigate 
before the 5.4 release.

I didn't take notes at the time, so I am summarising now:
* We've managed to make 6-month releases
** No change in schedule time: we want to continue doing 6-months
** Modulo adjustments so we don't release too close to vacation periods

* Release process is improving
** Ability to do package creation much more quickly
** Unification of packages with enterprise/commercial will also reduce workload

* How long should long-term releases be?
** More than every 2 releases
** Probably every 18-24 months (3 or 4 releases)

* First LTS release should be either 5.3 or 5.4
** Digia wants to do a business check first and will let us know
** 5.3 is a good candidate because we focused on stability

* Doing LTS buys us a few benefits:
** We can deprecate platforms and compilers after the LTS release
** Targets to be dropped as soon as feasible:
*** Windows XP
*** OS X 10.6
*** MSVC 2008
*** GCC < 4.6

* Procedure:
** Bugs to be fixed should be security bugs, P0, P1
*** P2 can be fixed, exceptionally, if no workaround is possible
** Fix is applied to the LTS branch and then merged to the next releases
** Releases should be based on amount of changes made, like what we're doing 
for 4.8

Link:
http://qt-project.org/groups/qt-contributors-summit-2014/wiki/Long_term_releases
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center