When I took over Quest, I was intrigued to see its history. Alex did some retrospectives in some blog posts, allowing a timeline to be constructed.
The roots of Quest, up to Quest 1.0, from Alex’s first game when he was 11 to the first Quest. https://blog.textadventures.co.uk/2013/11/07/quest-is-15/
From Quest 1.0 to 3.0, seeing the introduction of a GUI for writing games. https://blog.textadventures.co.uk/2013/11/07/quest-is-15/
From Quest 3.0 to 3.5, via multi-player. https://blog.textadventures.co.uk/2013/11/27/15-years-of-quest-part-3-2000-2004-experimenting-with-multi-player/
Part 3 indicated that he intended to write more, but I have not been able to find it. His next blog post indicates he got a proper job, so perhaps he never got around to it.
Quest versions 1 to 4 were a development of the same system. Quest 1 consisted of a player and a file format - a format quite unlike the XML format of Quest 5, but one that would be developed across the first four version.
With Quest 2, we got an editor and an update to the player. The player even at this time looked like the modern interface.
07/Nov/98 Quest 1.0 released
??/Aug/99 Quest 2.0 released, with beta version of the QDK editor
??/Nov/99 Quest 2.1 released, with play screen laid out as we know it today
??/Jan/01 Quest 2.19 released
??/Sep/01 Quest 3.0 released (with a short-lived multiplayer option)
??/Jun/02 Quest 3.1 released
29/Jun/03 First forum post (or first I could find anyway)
??/Dec/03 Quest 3.5 released
??/Jan/04 QuestNet Server first and only version released
17/Jan/07 Quest 4.0 released
02/Feb/07 Quest web player goes beta. Previously players could only download games to play, now they could play them in the browser.
Quest 5 was a big change. I get the impression the code was entirely written, now using C#. The file format was entirely different, using XML. The new interface was HTML. Another big change was that Quest went open source, and was now free to both edit and play. https://blog.textadventures.co.uk/2011/08/30/quest-5-0-is-out-now/
I joined the Quest community in the Summer of 2011, when the beta release of Quest 5 was out.
17/Jul/11 Quest 5 tutorial released (Bob and the defibrillator featured in the tutorial for earlier versions by the way).
01/Aug/11 My first forum post!
30/Aug/11 Quest 5.0 released
11/Jan/12 Quest 5.1 released
12/May/12 Quest 5.2 released (a web version of the editor)
14/Jan/13 Quest 5.3 released (updated interface using Chrome, web fonts, map, changeable POV, light/dark)
28/Mar/13 Quest 5.4 released (text processor, code view for scripts, JS object; some XML attribute names changed - which can cause problems if opening games from earlier versions)
05/May/13 Quest 5.4.1 released (exits with scripts need an attribute set to make the script run)
01/Mar/14 Quest 5.5 released (customisable UI, the Features tab and a contribution from me)
03/Aug/14 Quest 5.5.1 released
??/Feb/15 Quest 5.6 released (no blog post for some reason, so hard to find what got added, but a forum post indicated it was mostly a bug fix)
19/Sep/16 Quest 5.6.3 released (Alex’s last release)
11/Jan/17 Alex officially leaves Quest and textadventures.co.uk
19/Jul/17 Quest 5.7.1 released (there was no official 5.7.0!)
02/Feb/18 Quest 5.7.2 released