The Solr Operator relies on various settings and capabilities in Solr.
Every release of Solr comes with new features, but we can't expect users to be running the latest released version of Solr.
We aim to support a range of Solr versions, and thus build the operator in a way that will work for each of those versions.

There are optional features we can build into the Solr Operator, such as GCS or S3 backups, which are only supported in Solr 8.9 and 8.10 respectively.
Because these are not turned on by default, we don't need to mandate that users use at least an 8.9 or 8.10 solr version.

However there are many Solr features that we will want to make use of, by default, that will reduce the complexity of the Solr Operator or give additional options to the users.
We should document these features and note the version of Solr that they are introduced in.
Therefore whenever we upgrade the minimum supported version of Solr, we can go through and make all of the changes that are now guaranteed to be supported.

e.g. if we are changing the minimum supported version from 7.6 to 8.5, then we can look at this documentation for the features we care about added in 7.7, 8.0, 8.1, 8.2, 8.3, 8.4, and 8.5, and go and add support for them in the Solr Operator.