SharePoint Excel Services Application Error - Compatibility Range mismatch between the Web server and database

I recently worked on upgrading a 2010 content database to 2013, and once the upgrade had completed, I wanted to test the Excel Services Viewing Application.  I was quickly greeted with the "cannot load workbook" error message and began digging in ULS.  Here is the error message I found:

"Failed to load 'http://URL/book.xlsx' with error: 'Unable to open workbook due to unexpected exception: Microsoft.Office.Excel.Server.Host.HostFileException ---> Microsoft.SharePoint.Upgrade.SPUpgradeCompatibilityException: There is a compatibility range mismatch between the Web server and database "SharePoint_Content_SalesPortal", and connections to the data have been blocked to due to this incompatibility. This can happen when a content database has not been upgraded to be within the compatibility range of the Web server, or if the database has been upgraded to a higher level than the web server. The Web server and the database must be upgraded to the same version and build level to return to compatibility range."

I didn't dig into the specifics of WHY this error occurred, but I definitely remember running into security issues when installing Office Web Apps in 2010, and sure enough this error message turned out to be a security problem.  I granted proper security access to the Service Account used by the Excel Service Application using powershell and fixed the issue.  The powershell I used can be found below:

$webApp = Get-SPWebApplication http://webappurl
$webApp.GrantAccessToProcessIdentity("domain\username")

Hope this helps someone out there!