Dovecot - Upgrade Solr 7.7.2 to 8.4.1

[Domenico Pastore]

Hello,
I have Dovecot configured with Solr for the indexes.

I have need your support for upgrade solr 7.7.2 to 8.4.1.
Solr 7.7.2 has a security issue CVE-2019-12409.

It's possible upgrade of Solr? 
Dovecot work correctly with Solr 8.x? 

The Solr documentation recommended after updating:
"It is always strongly recommended that you fully reindex your documents after a major version upgrade."

There are tips for Dovecot?

Br,
Domenico