After Upgrading to 5.5.2; @username is not working on streams

[kumaresan]

hello,

After upgrading to the version 5.5.2 and Version 5.5.3;
a. not able to use @username on the Stream comments
b. while assigning a user to any (may it be contacts, account, leads or opportunity) active users are not visible; only users created after the upgrades are visible while typing few words in ajax

appreciate any solutions to this issues.

Regards,
Kumaresan