Source:
https://armoredwarfare.com/en/news/general/update-0250-now-available
The TOS-1M changes were originally supposed to take place last November, but for some reasons they didn't actually happen back then.
Both AFT-10 and BM Oplot buffs seem to be in response to requests on last month's stream, where SS also commented that both vehicles weren't doing well.
IT-1, Object 287, and K21 XC-8 received their coaxial machine guns as part of undocumented changes in 0.235, but are mentioned now.
As for other vehicles with machine guns mentioned in the patch notes, it looks like that they were the ones that got left out from previous machine gun elevation fixes in 0.155, and finally got theirs fixed this week.
There is a new unknown consumable slot to the right of PvE-exclusive Field Repair Kit slot in match, where the shortcut key is shown to be "loc_".