Where has subsurface gone?

I have just downloaded the new version of Blender on my mac and can’t find the subsurface buttons or the vertex decimator for that matter. I have tried looking under the various mesh menus. Any help appreciated. Is there a website that describes these kinds of changes for a newbie like myself? Thanks.

Yes, Blender.org Release Logs.

Subsurface is now under the dropdown list called ‘modifiers’ in Edit (F9) buttons. I think Decimate was moved there as well.

press f9
click on select modifier select subsurface