Are Adobe good at maintaining older versions?

Updates and upgrades are confusing. 

Peru Bob is right.  PrE 14 became 14.1.

However, there were more minor updates than that.  Adobe Camera RAW ("ACR") is primarily a photographer's tool.  It is essentially a set of tables that interpret the proprietary, unprocessed formats of camera manufacturers.  Adobe updates it every couple of months to include the newest cameras released to the market.  If you have a brand new camera and use Photoshop or Lightroom a lot, it is important. 

Since Premier Elements can be used to make "slide shows", it needs to be able to accept raw photo files too.  So, during the lifespan of a PrE version, it will get the ACR updates along with the photo programs.   Version 14 started with ACR 9.0 and finishes with ACR 9.6. 

If you have a camera produced after the end of version 14 and want to use raw format photos in PrE, you will need to buy version 15.  

One of the most senior regular contributors here will post that PrE needs to have all photos used in a project be resized and in a JPEG format.  When I see him do that I will counter that I've created projects with up to a 100 full sized, untouched raw photos.  The project was huge and the files big.  Premier Elements had no trouble and did not balk.