update to crashed the site

The update to took several minutes and crashed the site and we had to restore website from a backup. We tried the update 2 times and both times it failed.

The update left the .maintenance file in the site root and when trying to access the site we would get the following message:
"Briefly unavailable for scheduled maintenance. Check back in a minute."

We will NOT be updating to - we will wait for next version which hopefully fixes this bug.