CM patch 23631 corresponds to 6.3.115.1 which is above the service pack 6.3.11. So the PSN020262u is not applicable on your CM release 6.3.115.1.
The latest release for your CM till date is 6.3.17/117.0. Kindly check for compatibility matrix before proceeding with any upgrades.
Kindly refer below link as well for compatibility.
https://support.avaya.com/downloads/download-details.action?contentId=C20090710154815434625607&productId=P0001
Kindly refer below KB link which will guide you to check compatibility of CM with other Avaya product releases.
https://support.avaya.com/ext/index?page=content&id=FAQ112716&group=UG_INTERNAL
Your CM is on base load 6.3.0.141 for which the service pack corresponding to is 6.3.115.0 and the latest service pack is 6.3.117.0
For CM with base load 6.3.0.124 corresponding service pack will be 6.3.15.