Yes after the SegWit update, you need to update to Version 1.2 - Miners and Stakers should have updated a lot earlier.
Updating to 1.2.0 appears to have solved the problem, though I won't know for sure for at least a day because it seems the new wallet program has to download the entire blockchain all over again.
That doesnt disrupt your staking, your coins are still mature.
Perhaps, but my balance is now 0... The new wallet has both of the addresses I generated in the original wallet, shows the most recent transactions from before the upgrade, and required the same password to unlock it for staking, but balance is 0.
If you ever wonder why people are slow to upgrade their wallet this is a prime example why.
EDIT - I scrolled back through the post history and found a recommendation by you to run trezarcoin-qt with the switch -zapwallettxes=1 so I am trying that. ...waiting for rescanning to complete... and.... *most* of my balance is back - the most recent stakes I received when still running the old wallet have disappeared. Still, I seem to have solved the problem myself and I must say I really like the changes you made concerning staking.