I installed SharePoint Server 2013 SP1 today on RTM based environment.

1. I ran psconfig -cmd upgrade -inplace b2b –force on every server in the farm. Then ran the configuration Wizard
   
2. I saw that my BDC DB was still in Compatibility mode. Below PowerShell script fixed it.
   

(Get-SPDatabase | ?{$_.type -eq “Microsoft.SharePoint.BusinessData.SharedService.BdcServiceDatabase”}).Provision()