Are you thinking of migrating your EPiServer CMS 4 site to EPiServer CMS 5? If so, we highly recommend that you first read the information below.

Which version of EPiServer CMS 4 must I have to migrate to CMS 5?

The migration tool supports migration of EPiServer CMS sites from version CMS 4.62 to CMS 5 SP2.

What if my EPiServer CMS site is based on 4.51?

Then you must first upgrade the EPiServer CMS site to be migrated to 4.62 using EPiServer CMS Manager. EPiServer CMS 4.62 is the only supported version for migrating to EPiServer CMS 5.

What are the basic steps involved in the migration process?

The EPiServer CMS 4.62 database is migrated in place and receives all the necessary configuration on the target CMS 5 site. After migration, the CMS 4.62 database has been converted to the CMS 5 schema, the CMS 5 site has configuration settings that map to the CMS 4.62 configuration, and its connection string points to the converted CMS 4.62 database.

How should I prepare my EPiServer CMS 4 site for migration?

The steps that must be carried out before you can migrate your site are explained in the Migration Tool technical note. The article Preparing for EPiServer CMS 5 also contains some useful information about what to think about before migrating to EPiServer CMS 5. 

Problems?

During migration if you experience problems and you recieve the message in the migration log: "System.ArgumentException: Cannot widen from source type to target type either because the source type is a not a primitive type or the conversion cannot be accomplished."  This is arises because the server that you are migrating to, does not have EPiServer CMS 4.62 already installed 

Before commencing migration you must install the EPiServer CMS 4.62 assemblies onto the server's GAC.  For further details regarding this, see the EPiServer Migration Tool technical note.