Ubuntu 20.04 (fresh yesterday)
When running the latest installer (iRedMail-1.3.2) it fails when verifying packages, here's the screen dump.

ngranny@micro:~/Downloads/iRedMail-1.3.2$ sudo bash iRedMail.sh
< SKIP > Function: check_new_iredmail.
'multiverse' distribution component is already enabled for all sources.
'universe' distribution component is already enabled for all sources.
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [111 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [98.3 kB]
Fetched 317 kB in 2s (170 kB/s)     
Reading package lists... Done
[ INFO ] apt update ...
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Get:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [111 kB]
Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [98.3 kB]
Fetched 317 kB in 2s (172 kB/s)                                     
Reading package lists... Done
[ INFO ] Fetching source tarballs ...
[ INFO ] + 1 of 5: https://dl.iredmail.org/yum/misc/iRedAdmin-1.1.tar.gz
[ INFO ] + 2 of 5: https://dl.iredmail.org/yum/misc/mlmmja … 0.4.tar.gz
[ INFO ] + 3 of 5: https://dl.iredmail.org/yum/misc/iRedAPD-4.6.tar.gz
[ INFO ] + 4 of 5: https://dl.iredmail.org/yum/misc/netdata-v1.26.0.gz.run
[ INFO ] + 5 of 5: https://dl.iredmail.org/yum/misc/roundc … ete.tar.gz
[ INFO ] Validate downloaded source tarballs ...
misc/iRedAdmin-1.1.tar.gz: FAILED
misc/mlmmjadmin-3.0.4.tar.gz: OK
misc/iRedAPD-4.6.tar.gz: OK
misc/netdata-v1.26.0.gz.run: OK
misc/roundcubemail-1.4.9-complete.tar.gz: OK
sha256sum: WARNING: 1 computed checksum did NOT match
    [ FAILED ]
<< ERROR >> Package verification failed. Script exit ...

I tried downloading it multiple times and from different machines-- same problem.

Thanks

Nick