Hello,
We tried to upgrade from 2019-02-08 to 2019-04-19 and the client did not start after the update.
We had to copy the client folder from other place which was working.
I can see the errror "Failed to open initial window, "DBUsageWClass".
Any ideas why this happened? We had no problems upgrading other client, though.

2023-06-02 15:09:45 Database ID changed from: 00000000000000000000000000000000 to: 440BDACD209F4E1095C81C004BD237BE

2023-06-02 15:09:51 Database ID is: 440BDACD209F4E1095C81C004BD237BE
2023-06-02 15:09:51 Duration 0.00 seconds
2023-06-02 15:09:51 File Imported GBR/DBDEF.TXT
2023-06-02 15:09:51 Failed to open initial window, "DBUsageWClass"
2023-06-02 15:09:51 8.5 2023-04-19 (build 85550290)
2023-06-02 15:09:51 Close database
2023-06-05 10:41:49 *** running with new mail receiving and parsing ***
2023-06-05 10:41:49 *** Using Clock Replacement ***
2023-06-05 10:41:49 *** using a freelist to keep track of free space ***
2023-06-05 10:41:52 Database ID is: 440BDACD209F4E1095C81C004BD237BE
2023-06-05 10:41:53 Failed to open initial window, "DBUsageWClass"
2023-06-05 10:41:53 8.5 2023-04-19 (build 85550290)

2023-06-05 10:41:53 Close database