This has been a long time coming and Phil Wareham (designer) has put a huge amount of work into this redesign, along with an overhauled docs site, plus other stuff.
Work is ongoing with Textpattern 4.7, with a whole bunch of new stuff, parser improvements, tags and other things. Exciting times!
https://github.com/textpattern/textpattern (Textpattern CMS)
https://github.com/textpattern/textpattern-com-website (Textpattern website)
https://github.com/textpattern/textpattern.github.io (Textpattern docs)
New (and lapsed) users are always welcome.
But what happened to Txp5, with several blog posts years ago? Is that effort dead? Rolled back into 4.x?
My understanding is the big plans for Textpattern 5 were reined in following discussions with the plugin developer base, among others.
There are significant changes within the 4.x releases, but there's currently still a single-jump upgrade path from the earliest releases to the latest. My understanding is that _very_ old versions (early 4.0.x releases) will no longer be supported in this one-step upgrade, but anecdotally a large majority of sites run 4.6.x or 4.5.x, so it's not a huge concern.
The overhaul was done with a lot of love and it shows.