for the record, the default mono version that comes with MX 19 is:
$ mono -V Mono JIT compiler version 5.18.0.240 (Debian 5.18.0.240+dfsg-3 Wed Apr 17 16:37:36 UTC 2019)
after adding the official latest stable mono release and upgrading $ sudo apt upgrade
I landed with
$ mono -V Mono JIT compiler version 6.8.0.123 (tarball Tue May 12 15:15:28 UTC 2020)
for the record, the default mono version that comes with MX 19 is:
$ mono -V
Mono JIT compiler version 5.18.0.240 (Debian 5.18.0.240+dfsg-3 Wed Apr 17 16:37:36 UTC 2019)
after adding the official latest stable mono release and upgrading
$ sudo apt upgrade
I landed with
$ mono -V
Mono JIT compiler version 6.8.0.123 (tarball Tue May 12 15:15:28 UTC 2020)