Pretty much like the title says:
After updating game and mod, the previously earned general trade bonuses are gone.

What trade bonuses? Like trade productivity?

Edit: I see. This whole migration thing is incredibly complex, and I can't just build a testing suite to ensure that every scenario is tested for. I'm sorry for the mess. 1.5.8 will add your bonuses back, hopefully all of them, because I can see something that was missed, again. You won't have to roll back.

Yes, trade productivity.
Thanks for fixing it.

1.5.8 is released and should fix up all issues introduced from 1.5.6's item buff rebalance.