Subject Firebird 2.5 ppa repository for Ubuntu 18.04

There is reference to installing Firebird 2.5.x on Ubuntu on the website at  but this information is very old.  The repository that is referenced does not seem to work with Ubuntu 18.04.  When I attempt to add it to my sources and then update, I get the following error:

E: The repository ' bionic Release' does not have a Release file.

N: Updating from such a repository can't be done securely, and is therefore disabled by default.

Is there a more up to date repository for Firebird 2.5 for Ubuntu 18.04 LTS that any one can point me to?  I can install from the script, but it doesn't support inetd, etc. and I'm going to have to manually set all that up.  I'm sure that a DEB package for this will do all of that automatically.  I am unable to use FB 3 yet, so I need this for FB 2.5.