Comment 2 for bug 1805040

This can't be a good answer.

For external software providers, if they want to ship a program linked against libreadline, and support it on multiple LTS versions of Ubuntu (from 14.04 to 18.04), this makes it impossible for them.

There's no way they can force a link against libreadline5, unless you provide a libreadline5-dev (which you don't, on nay of those versions - the only libreadline-dev will link against libreadline6 on 14.04 and 16.04, and against libreadline7 on 18.04.

So there's no way to link a single executable against libreadline-dev and have it run on all of 14.04, 16.04 and 18.04.

You really _must_ ship a libreadline6 in addition to libreadline5.