From the dashboard, Systems & Settings, Backup & Restore, Update concrete5 when I click on Update Concrete5 I get:
HTTP 500 error
That’s odd... the website can’t display this page
The site may be under maintenance or could have a programming error.
Try this
Go back to the last page
Try contacting the website’s owner

I am currently using:
# concrete5 Version
Core Version - 5.7.5.13
Version Installed - 5.7.5.13
Database Version - 20160615000000