Context

As projects build more documentation versions, they might become deprecated.
Besides, for a version that is not considered stable, but actually it is the next release available, the theme shows an incorrect message:

> You are not reading the most current version of the documentation.

Proposal

1. Add in conf.py the option to tag versions as STABLE, UNSTABLE, or DEPRECATED.
   The implementation could look like this:

STABLE_BRANCHES = []
DEPRECATED_BRANCHES = []
UNSTABLE_BRANCHES = []
BRANCHES = STABLE_BRANCHES + DEPRECATED_BRANCHES + UNSTABLE_BRANCHES
smv_branch_whitelist = multiversion_regex_builder(BRANCHES)

2. Edit layout.html with new caution messages for every version. The caution message shown for every status could be:

STABLE_BRANCHES:

You are not reading the most current version of the documentation.
If you want up-to-date information, please have a look at .

UNSTABLE_BRANCHES:

You are reading an unstable version of this documentation.
If you want up-to-date information, please have a look at .

DEPRECATED_BRANCHES:

You are reading a deprecated version of the documentation.
If you want up-to-date information, please have a look at .