SOLR Release Versioning Scheme

There has been a lot of talk on the SOLR mailing lists (see http://markmail.org/message/o6b2lhuqpi4tefyo ) regarding the release version number scheme for Apache SOLR. We can use this Wiki page to collect thoughts on the subject, and eventually (hopefully) document a simple, clear (and short!) process here.

References

http://en.wikipedia.org/wiki/Software_versioning

Proposals

Here are some of the proposals put forth:

In this type of scheme, all n's in a series are expected to be at least backwards compatible with n-1 through 0-9, but all M+1's aren't necessarily compatible with M or M-1.