With Moodle 3.2 we have introduced the new Boost (BS4) theme, becoming the default one for all new installations, while existing sites continue using what they were using before (usually a bootstrap/clean/more based theme, as far as the old base/canvas bases were sent to contrib, sort of deprecating them).

This issue is about to guarantee that, while Boost is the prominent theme and lots of changes and improvements will happen on it, the previous bootstrapbase (BS2) remains completely functional and working ok.

This has implications at different stages of the cycle, namely:

• development: what needs to be taken into consideration, use bs4 selectors together with bs2, try to (slowly) homogenize templates (moving to the best alternative that seems to be renderer+template)... any consideration.
• testing: How to, continuously, have tested the BS2 bases, ensuring no regressions happen. This includes both manual testing (basically each change having ui_changes or theme changes, should be visually tested in bot themes). And also automated testing, ensuring all navigation/interactions continue working ok.
• qa: Giant smoke testing of BS2 is enough, or do we need to run all MDLQAs under both themes (we have done that for 3.2 and has worked ok, so far).
• ... (feel free to add more main points).

And that's this, any implication that you can imagine, comment, recommendation, is welcome. We should end with an agreed policy, easy to understand and with links to the detailed (technical) information helping to support the policy.

Ciao