I'm not expecting that, it would be different to how their process has worked in the past. It would be high risk for them to drop the refactored code on millions of casual players without it passing through beta scale testing first.
I expect the current 1.4.2 which has been on beta for so long to move to main branch and mods updated for 1.4.2 will still work on it.
1.4.3 will come to beta, and it will be largely the same to play as 1.4.2, but it has been code refactored under the hood and that is likely to break mods.
Assuming it does play out that way, it means if you need mods to enjoy the game you can just play main branch (which will be the 1.4.2 we've all come to know and love... and get bored of) until mods are updated. You won't miss much in the way of new features or content since 1.4.3 is focused on refactor, not features or content.