Does bugfixes backported from fresh to still branch?

I have no reasons to upgrade from LO 5.3 to 5.4 except, maybe, bugfixes. So, I have a question: if some bug fixed in LO 5.4.x and this bug exist in 5.3.x too, will this bug be fixed in next version of LO 5.3.x too?

Possibly it will get to Still. Not always. Any bug is fixed initially in master (currently, it’s towards 6.1); then it gets backported to either Fresh, or to both Fresh and Still - depends on developer, and the amount of work (and sometimes it’s impossible to fix it in older branch, because it’s some change in a newer branch that made it possible to get fixed, and it’s impossible to get that change to older branch reliably).

I have emphasized the word Still above, to stress one thing: currently (2017-12-23), the Still branch (that might ever get an update) is 5.4! 5.3 had its last update (5.3.7) in October, EOLed in November, and will never receive a fix again. You may see that on Release Plan wiki page.

Also, there exists commercial support, when paying customers receive long-support contracts, and may get bugs fixed for them (on contractual terms) in versions they agreed upon (that might be much older version, like 5.1) from the company or individual they contracted - if that fix is possible for that version at all.

I understand. Thanks for the quick and detailed answer!