Bug#960243: zimlib FTBFS with ICU 67.1

I downloaded the build logs  and filtered them to show the missing symbols that were not already marked as optional. plugwash@thinkpad:~$ wget -O zimlib.log 'https://buildd.debian.org/status/fetch.php?pkg=zimlib&arch=amd64&ver=4.0.4-5%2Bb1&stamp=1591384179&raw=0' plugwash@thinkpad:~$ html2text

Bug#960243: zimlib FTBFS with ICU 67.1

Source: zimlib Severity: normal Justification: fails to build from source (but built successfully in the past) Tags: ftbfs Hi, Soon the ICU transition will start. Your package FTBFS with the ICU 67.1 version, currently in experimental. The reason is symbol changes due to it in your libzim4 librar