SDK update available but it's already up to date

[BIF01]

atlas-run command shows the WARNING message:

************************************************************
Version 8.2.6 of the Atlassian Plugin SDK is now available.
Run the atlas-update command to update.
************************************************************

but atlas-version command shows it's already up to date:

ATLAS Version: 8.2.6
AMPS Version: 8.1.0

Any advice? Thanks in advance.
Cheers.