Managely allows the users to change the next check number.
Note: Unlike the next customer number, next invoice number, next vendor number and next purchase order number which are all found under Setup -> Under Company -> System Defaults, this feature is located in a different place.
Follow the steps below to change the next check number.
The next check number can be found under each bank.
In Managely, go to GL -> Bank Accounts:

Click on the bank name:

Click Edit:

Adjust the next check number and click Save:

Note: if you have multiple banks set up, the steps need to be repeated for each bank that needs the next check number adjusted.