Upgrading Drupal

I'm using the Migrate module to migrate content from a D6 site into a new D7 site.
All my fields seem to be coming over nicely, but I haven't been able to find any examples or documentation of how to move a Matrix field from D6 to D7.

Initially I wanted to migrate the Matrix Field to a Field Collection in D7 but didn't find any information on that and thought maybe it would be easier to move to a Matrix Field in D7.

If anyone has an example of a field mapping either from
Matrix > Matrix
or
Matrix > Field Collection

I am a tester of the UI for Drupal applications. We are currently at 7.34 and have 5 applications. When we upgrade, will there be anything noticeable the UI testers should look for?

I run a subscription based website, with a few thousand subscribers. I am currently running it with Drupal 6 and Ubercart. I have rebuilt the site on Drupal 7, using Commerce. Now I want to migrate my user database to the new site, but am perplexed at trying to find a way to move the Ubercart-generated role expirations into the new Commerce system. Does anyone have experience with this, or suggestions of how to proceed?

Thanks in advance.

I upgrading my Drupal 6.37 to Drupal 6.39.

While steps have done. The error message below appeared.

i migrate a website to centos6.5 , the cron not work

Any ideas on a possible cause for this error? I tested the upgrade on my own site first, which worked like a charm. The second site I upgraded (other provider) is stuck with a 500 internal server error.