Fellow Sage CRM enthusiasts, I'd like to pick your brains on upgrades.

We have a Sage CRM 7.1 implementation currently using SQL Server 2008, on a Windows 2008 Server. It includes a lot of customisations and developments, some pretty heavy.

We would like to upgrade to 7.3.

Do we have a how-to guide on how to upgrade, including best-practice on upgrading developments?

Some of the questions we are asking ourselves are:

- In the event we decide to change the server: should we install our 7.1 on a SQL Server 2008 on the new server, and then upgrade SQL Server? Or do we have a faster way of doing this? (e.g. install SQL Server 2014, install 7.1 on that version, restore database (?) then upgrade (?))

- In the event we do not change the server and just upgrade SQL Server and Sage CRM, same question: Should we just upgrade SQL Server and then Sage CRM? or should we install a separate instance of SQL Server and in that case what are the steps to perform the upgrade?

- What is the recommended method to upgrade customisations and developments? do we just do the upgrade and then review the customisations?

Any insight or doc you have would be welcome :)

Thanks!