During some lab testing of a Lync Server 2013 Enterprise front-end pool upgrade to Skype for Business 2015 Server, issues with the SQL database were reported by the Front End Servers in the form of an incorrect version of SQL found after going ahead too quickly. Simply put, replication should have been confirmed before going ahead and wasn’t.
Two Services would start and then stop. They were:
Lync Server File Transfer Agent
Lync Server Master Replicator Agent
Despite trying to restart these services, they would stop almost as soon as starting. Over to the event viewer to see what was happening:
Event ID 1021 Source LS File Transfer Agent Service
Microsoft Lync Server 2013, File Transfer Agent successfully registered with the back-end, but a schema or sproc version mismatch was detected. The service will not start until this problem is resolved.
Database version: Actual = 10.15, Expected = 10.13.
Cause: Installation error.
Resolution:
Ensure both Microsoft Lync Server 2013, File Transfer Agent and back-end were installed or modified by the same installation package.
Also accompanied with
Event ID 1004 Source LS File Transfer Agent Service
Microsoft Lync Server 2013, File Transfer Agent service is stopping.
And then Event ID 1005 Source LS File Transfer Agent Service
Microsoft Lync Server 2013, File Transfer Agent service has stopped
It seemed like the XDS database had upgraded but the server was not expecting the newer version.
Replication was not successful as shown here

Replication not complete
Looking into the XDS database and checking the DbVersionSproc setting showed me it was set at 15

SQL XDS Database Version
A blog post from Georg Thomas here had the solution needed and what the DbVersionSproc Value should be for 10.13!
The expected version of 10.13 is DbVersionSproc 13.
Georg confirms in his blog post:
‘Using SQL Server Management Studio, I opened the xds database and navigated to the dbo.DbConfigInt table. Here I modified the DbVersionSproc value from 15 to 13.’
‘I went back to the failing services and restarted it. Voila! It starts. I go and set the value back to 15. A few seconds later my topology is fully replicated.’
All credit to Georg!
After starting the two services you will receive these Event IDs:
Event ID 1003 Source LS File Transfer Agent Service
Microsoft Lync Server 2013, File Transfer Agent service has started
C:\Program Files\Microsoft Lync Server 2013\File Transfer Agent\FileTransferAgent.exe v5.0………
Event ID 1012 Source LS File Transfer Agent Service
Successfully read Central Management database information from AD connection point.
Event ID 1036 Source LS File Transfer Agent Service
Microsoft Lync Server 2013, File Transfer Agent service is running in active mode.
Event ID 1019 Source LS File Transfer Agent Service
Successfully connected to back-end using the connection string of
Data Source = XXXXXXX;
Database = xds;
Max Pool Size = 5;
Connection Timeout = 60;
Connection Reset = false;
Enlist = false;
Integrated Security = true;
Pooling = true
EventID 2003 Source LS Master Replicator Agent Service
Microsoft Lync Server 2013, Master Replicator Agent service is starting
Event ID 2004 Source LS Master Replicator Agent Service
Microsoft Lync Server 2013, Master Replicator Agent service has started
Event ID 2021 Source LS Master Replicator Agent Service
Successfully read Central Management database information from AD connection point.
Event ID 2033 Source LS Master Replicator Agent Service
Microsoft Lync Server 2013, Master Replicator Agent service is running in active mode.
Event ID 2008 Source LS Master Replicator Agent Service
Successfully connected to back-end using the connection string of
Data Source = XXXXXXXX;
Database = xds;
Max Pool Size = 5;
Connection Timeout = 60;
Connection Reset = false;
Enlist = false;
Integrated Security = true;
Pooling = true;
It is also stated that modifying the SQL databases is done so at your own risk. If you need to do this in production, backup everything first and confirm the backup!
All the best!
Austin