If you're on a Windows platform, the new version must be on a different server as they use different versions of ServletExec. As far as migrating goes, it should be difficult but it depends on what components. FEXes and MFDs can just be copied. There are migration procedures for MRE and Report Caster. Also, 436 defaulted to CGI and 52 defaults to Servlet. If using CGI, I highly recommend switching to Servlet.