I dont know where I heard this from, it might just be in development.

However, take a look at an ubuntu mirror site eg:

http://ftp.cica.es/ubuntu/ubuntu/pool/universe/f

and you will clearly see firebird2 and firebird2.0, with files
referring to 1.5.3 and 2.0 respectively.

I dont know how you get to these as "apt-cache search firebird2" just
gives me 1.5.3, guess its a repository/source.list thing.

Ian