Palemoon versus 18.04 Ubuntu repo. versus key

[Moltke]

Hi,
I have a problem with Palemoon browser.It stopped updating and displays a message saying that the key is invalid.I remode the PPA and key et redid the install procedure but have the same error.
I'm guessing the 20.04 version should be OK but I was just wondering if I should just remove the PPA/Key and install the .deb file manually.
Anyone else using this browser on previous Ubuntu 18.04 / Linux Lite 4.x ?

As stated here https://www.palemoon.org/

It is not necessary to install Pale Moon to use it. Pale Moon for Linux is distributed as a bzipped tarball that can be extracted and run from any location on your system.

That's what I do; just download the .tar file, extract and run pale moon, when a new version is released, I just download that and rename the old one to something like, pale moon.old to keep it around just in case, extract the new version and run.