I had to postpone the update.
Today I have tried to update 1.9.1 to 2.0.15+build.2016.11.04.23.56.32.d216344a5, but again when I change a profile in the front-end or back-end I got the error:
1054 Unknown column 'connections' in 'field list' SQL=SELECT connections FROM ..._comprofiler WHERE id=
Please advise