Can you still play your 1.4.3 beta save in the new 1.5.0 beta?
Edit: I just tried my 1.4.3 save. It starts but I wouldn't recommend it. The whole mainquest got reset and things like perks, levels, and troop size are messed up.
Edit2: Sorry, I've made a mistake and loaded a save from a much older modded version. Because the savegame names and dates got reset in 1.5.0 they appeared at the top and I thought it was my most recent game. I am downloading 1.5.0 a second time now and will report back if there will be any direct problems with the save/troop size.