I have renamed the group for a content type in the site settings for my site. But when I run code checking on SPListItem.ContentType.Group it is returning the old content type. If I check the content type using SharePoint Manager 2013 I can see that the group is set to the new one that I gave it. But when I check the group name of the content type of the pages list it is the old name. How do I update the group name in each pages list in all the sub sites?

Hi,

Please try to use the following PowerShell Script to rename the content type group.

$site = new-object Microsoft.SharePoint.SPSite("http://sp2013sps:8080");
$site.rootweb.contenttypes["TheContentTypeName"].Group = "TheNewGroupTitle"; 
$site.rootweb.contenttypes["TheContentTypeName"].Update($true,$true);

More information:

http://omourad.blogspot.com/2009/11/update-content-types-and-site-columns.html

Best Regards