Created attachment 845580 [details]
List of packages on the webserver after fixup

Versions: 
roundcubemail-1.4.10-1.1.noarch
php8-8.0.1-1.1.x86_64
php7-7.4.14-2.1.x86_64
php7-json-7.4.14-2.1.x86_64
libzypp-17.25.6-1.1.x86_64

Yesterday 2021-01-26 I did a dist-upgrade for Tumbleweed.  Some unknown
package sucked in php8, which obsoletes php7-json, which roundcubemail
requres (and likely others).  But roundcubemail was not forced out.  
I didn't notice, and roundcubemail died calling a nonexistent entry
point json_decode().  (It's used in 15 places.)  

There's some kind of dependency issue here, which I could not spot, 
but which needs to be tracked down and headed off.  Attached: the list
of installed packages on the webserver, after reinstalling php7-json.  

Workaround: zypper install php7-json ; accept its offer to de-install
php8.  Zypper didn't think there were any other dependent packages, and
I have not (yet) noticed any bad consequences either.  

Sorry, I couldn't figure out which component was relevant to this.
Could the triage person please pick a better category than "other"?