At the moment, the files should be backward compatible. I would suggest to keep a copy of the latest state before you switch back, just to be on the safe side.

I'm running 4.5.3 on 64bit Kubuntu 11.04 KDE 4.6.2, I've not experienced any performance issues until today but ONLY related to Payees.

After clicking the payees icon selecting a payee causes CPU to jump to 50% (dual core) and it takes 20 seconds before any transactions are displayed.

I didn't see this in previous Kubuntu versions and as I've already mentioned I do not have performance issues with any other parts of KMM.

My file is 266k. other stats:
Payees: 579
Institutions: 17
Accounts/Categories: 278
Current: 3 1
Savings: 12 7
Credit Card: 3 2
Investment: 17 2
Asset: 4
Income: 56 0
Expense: 145 0
Stock: 37 4
Equity: 1 0
Transactions: 2865
Splits: 5937
Schedules: 36
Prices: 5028

Hope this information is of some use.

I recently upgraded from Slackware64 13.1 to 13.37 so I also upgraded from Kmymoney 4.5 to 4.5.3. 4.5.3 was so slow as to be almost unusable. There would be massive delays when entering a new check/deposit/etc. When reconciling, it would take 5+ seconds from clicking on an item to it being marked as cleared. This is on an i5-750 system. Switching back to 4.5 brought all the speed back again.

NickElliott wrote:I'm running 4.5.3 on 64bit Kubuntu 11.04 KDE 4.6.2, I've not experienced any performance issues until today but ONLY related to Payees.

After clicking the payees icon selecting a payee causes CPU to jump to 50% (dual core) and it takes 20 seconds before any transactions are displayed.

This was fixed in SVN see https://bugs.kde.org/show_bug.cgi?id=268274