We have performed our upgrade process successfully 4 times prior without issue but now we can not seem to get past this issue:

When we run this command Upgrade using Mount-SPContentDatabase STS_Content_TFS -DatabaseServer <> -WebApplication <>, we receive this error:

There is a compatibility range mismatch between the Web server and database "", and connections to the data have been blocked to due to this incompatibility. This can happen when a content database has not been upgraded to be within the compatibility range of the Web server, or if the database has been upgraded to a higher level than the web server. The Web server and the database must be upgraded to the same version and build level to return to compatibility range.

We have tried services restarts, reboots, re-applying app poll and service accounts and even re-image of vm and nothing seems to work

We have also tried to run PSConfig.exe -cmd upgrade -inplace b2b -force -cmd applicationcontent -install -cmd installfeatures and are now getting Cannot open SPTimerV4 service on computer.

Hope someone can help, we are running out of things to try to resolve this. 

Many Thanks

Kim Bates

try this

stsadm -o addcontentdb -url <http://servername/> -databasename <databasename>