You’d need to be more specific about what went wrong - logs etc. It would be best to open a new topic about your specific issues as they’re not general issues with the v4.2.0 release. I’ll move your posts over now, and perhaps you can provide some more details about how you have things setup and what the problems you have are when you run migrate please.
I’d check that your shared hosting is using MySQL and not MariaDB. MariaDB is known not to work with 4.2.0 - see Xibo CMS v4.2.0 Released - #5 by pitoco02