I have several machines on my local network. I work on machine A, and run applications remotely using ssh -X on the other machines. Today I discovered that when I start Firefox on newly-upgraded machine B, it's actually starting the older version that's on machine A. This seems obviously wrong, and is certainly not what I want to happen. I want to run the newer Firefox that's on B, and have it display on A. Longer details: A runs OpenSUSE Leap 15.0. B runs Leap 15.4. I start an xterm on B with the command " "ssh -X -l me B", and programs other than Firefox I run from that xterm display on A's monitors, as expected. However, when I try to run Firefox (by typing "firefox &" on the command line, what actually runs is the older version of Firefox that is on A, just as if I'd started it with the same command on one of A's terminals. Is this a known behavior, and if so, is there a way to work around it? Or am I just doing something really stupid?