[PLAN] Future legacy support

[mfonville]

When Android N will be released, even more changes for our compatibility-mechanisms will probably have to be applied.

Our codebase becomes more difficult to manage over time, because of the many hacks for especially KitKat, but also a few for Lollipop 5.0, while install-base of these versions is becoming smaller over time.

The idea is to at some point drop development (but not support and builds) for 4.4 and 5.0. The moment Android N arrives is probably a good time for that.

Any major structural overhauls should still be done before doing this, so that the build-mechanisms between legacy and master can stay (mostly) the same, and that any changes can easily be cherry-picked to the legacy-branch.

TODOs:

• Index and perform any major structural overhauls that are overdue
• Fork master branch into a legacy branch (name should maybe include min or max APIlevel, e.g. legacy-19)
• Make buildbot checkout and use legacy for <=5.0 builds
• Remove lower than 5.0 code compatibility from master branch
• Remove lower than 5.0 Makefile targets from master branch
• Do keep the APK-packaging tools to keep accepting APKs from API 19 so that the APK repos stay up-to-date
• Find a maintainer for legacy that can cherry-pick and backport important changes from master.

[TheComputerGuy96]

Also, Open GApps 4.4 has some issues:

• Push token can't be obtained (or some issues like that)
• "Ok Google detection" menu doesn't open on Google app

[osm0sis]

@mfonville, should this just be closed? R will be out soon. 😛

I guess you could just strip the version-specific references out of it to keep it as a bit of a roadmap.

[mfonville]

Yeah, let's keep it as a road-map.

Still also most of the really weird compatibility quirks are to deal with versions below 5.1.
We will have to draw a line somewhere with dropping these really old versions for daily releases, when the install base becomes almost negligent, and just provide an old archived release that we know has high quality/stability.

So in general lines:

• a single archived build for 4.4, 5.0. Source code branched. (a PR would be welcome to check what code can be dropped)
• also to start limiting amount of build assets of 5.1 up to e.g. 7.1 for just the smallest versions.
• 8.0+ remains fully supported and daily builds