Referencing this question: How do you know what version number to use?
According to the above question, versions of beta projects should start with a 0.X, releases should be like 1.X, and rewrites of a project constitute a higher version like 2.X. So my question is: If I have a rewrite of a project that is in a beta state, what should it be versioned?
There are no rules about versioning,
You can use whatever you want to identify versions. Number, letters, codenames, dates, you decide.
Mhat matters more is what the people involved with your code expect (your users, other programmers, your boss, etc.) If you use numbers, then most people, for example, expect the version numbers to increase over time (but there are exceptions).
In your case, since you decided to use the x.y scheme, you can decide to start using major number 2 right now, and append a "beta" at the end of your version (e.g. Foobar.exe, v 2.0 beta) or keep the major version at 1 and use a special minor number to mark that it is "almost" version 2, something like Foobar.exe v 1.99).
