Photoshop elements 2018 files backwards compatible?

HI - I have downloaded the free trial of Photoshop Elements 2018 while I think about purchasing.  I have access to photoshop elements 15 in work and they are not planning on upgrading anytime soon.  Are photoshop elements files (psd's?) backwards compatible / openable in PSE 15 as I may want to work on files from work at home and then back in work?...or should I just buy PSE 15 for my home pc instead of 2018?

thanks