How to use dovecot with more recent versions of solr (8x, 9x)?

[jkdv at w3.org]

Hello,

dovecot version 2.3.13 (89f716dc2)

The dovecot solr installation guide [1] gives links and configuration info for
sorl 7.7.0. However, sorl was deprecated some time ago. Those links to 7.7.0
don't work anymore. Sorl is currently available in versions 8.11.2 and 9.1.1
[3].

Specifically, one section in the guide states [2]:

[[
Install schema.xml and solrconfig.xml

Copy doc/solr-config-7.7.0.xml and doc/solr-schema-7.7.0.xml (Since Dovecot
2.3.6+) to /var/solr/data/dovecot/conf/ as solrconfig.xml and schema.xml. The
managed-schema file is generated based on schema.xml.
]]

Could someone confirm me if those 7.7.0 configuration files are compatible with
8.11.2? A diff between those files and the ones from the 8.11.2 dist reveal some
changes, starting from the LuceneVersion.

If they are not compatible, could someone tell me what changes were done in the
doc/solr files that need to be replicated in the 8.x and 9.x versions?

The doc is very opaque there as it only states that you should replace those
files but doesn't go into details as to why, making it confusing on how
to upgrade to a new version of solr.

It would be great if the dovecot/solr doc page could be upgraded to reflect
the new versions of solr.

Thanks in advance for your help,

--jose

[1] https://doc.dovecot.org/configuration_manual/fts/solr/
[2] https://doc.dovecot.org/configuration_manual/fts/solr/#solr-configuration
[3] https://downloads.apache.org/lucene/solr/