Version consistency checks (v3.0.x and master)

[Alan DeKok]

Bjørn Mork wrote:
> I'd say supporting old dictionaries is crucial, given that you do mass
> attribute renaming like this:
> 
> https://github.com/FreeRADIUS/freeradius-server/commit/a5ad82aecc194f5f55153c351a62af9bb1c222a0

  Hmm... I'm generally against re-naming attributes.  It breaks
configurations, which is a bad thing.

  That being said, the dictionary format in 3.0 is largely compatible
with the dictionary format in 0.1, and earlier Livingston.  The only
incompatibilities are new data types (integer64) and formats (TLVs,
weird VSAs).

  So you can use older dictionaries with the new server.

  The problem is that some of the dictionaries are version-specific.  We
tweak them occasionally to fix data types, add new features, or new
server-side attributes.  It's a problem when people use old dictionaries
with the new server.

> The alternatives would be forcing simultanoues server upgrades or
> duplicated user databases.

  Yes.

  Alan DeKok.