Upgrade to 15.5 SP3

[Artik Lal]

How long should it take for this to happen ?

 

[eddv123]

Depends on how fast your internet access is, however if you are downloading the Service pack only (and not upgrading direct from an earlier version) I believe mine was no more than a few minutes.

You should receive an email when done to tell you that the services have restarted anyway.