I'll have to migrate the data from an 4.2 instance toward a 5.2g.
What is the best way to proceed ?
Is there any tool available in the platform or as an addon ?
Thnaks for your help
You can use Apache ManifoldCF to execute a crawling from 4.2 instance and then injecting contents against a 5.2 instance using the CMIS Connectors.
There is also a beta version of a specific Alfresco BFSI Connector that will generate the Bulk File System Import files ready to use with the 5.2 instance using the BFSI Tool.
Please see my presentation held at the Alfresco DevCon 2018 together with Luis Cabaceira:
Alfresco DevCon 2018 - Wrap up — Open4Dev
See also details about the Bulk File System Import Tool:
Using the Bulk Import tool | Alfresco Documentation
Hope this helps.
I think this blog will also help you,
Migration from 4.2 to 5.2
Retrieving data ...