I have noticed that the icons for some of the Calendar apps added into our Sharepoint 2013 Enterprise intranet site (when viewed under "Site Contents") show up as a large white calendar grid on a blue tile but others are shown as a smaller gold-coloured calendar on the same type of blue tile. Can anyone tell me what the differences mean? I can't find any references to this in the documentation. Thanks, John
You have SharePoint 2013 in use. All SharePoint 2013 apps are using the blue and white icons. All SharePoint 2010 apps are using the colored (gold style) icons.
See the following screenshots (all from SharePoint 2013 site contents)
This is a site after migration from SharePoint 2010 to SharePoint 2013. You will see the gold styled icons as the apps are SharePoint 2010 apps.
This is a screenshot of site contents in SharePoint 2013 just containing SharePoint 2013 native apps. You will see all of them being blue and white.
But it is possible to add SharePoint 2010 apps e.g. from a template to a SharePoint 2013 native site. Then you will see single gold style apps within SharePoint 2013 apps.
I hope this could answer your question "Can anyone tell me what the differences mean?".
If this answer helps please mark as answer. Thank you.