Thanks Yarden for your answer.

Unfortunately, apt-key is deprecated and your command line can't process. But you gave me tips to find:

curl -sS  https://releases.jfrog.io/artifactory/jfrog-gpg-public/jfrog_public_gpg.key | sudo tee /usr/share/keyrings/jfrog.asc && echo "deb [signed-by=/usr/share/keyrings/jfrog.asc] https://releases.jfrog.io/artifactory/jfrog-debs xenial contrib" > /etc/apt/sources.list.d/jfrog.list

that gave me the key lacking to have a functional apt update. My 7.98 version should be updated (not sure, I am at 7.98.13 and should be at 7.98.15). But to upgrade it to the 7.104.14 (last current version) I had problems.

Your apt-get install jfrog-artifactory-oss=7.104.13 gives me an error: the package is deprecated or missing

Artifactory help website (can we say it is really a "help"? ...) gives me:

curl -g -L -O -J 'https://releases.jfrog.io/artifactory/artifactory-pro-debs/pool/jfrog-artifactory-pro/jfrog-artifactory-pro-[RELEASE].deb'

which is ok with pro version efficiently downloaded but doesn't compute if I replace pro by oss version

I tried to download the file from https://jfrog.com/fr/community/download-artifactory-oss/ and I got a .gz file that gave me a directory artifactory-oss-7.104.14 where I expected a .deb file

I am a bit at a loss there to update Artifactory... The key error is fixed but I can't get new versions.