Prison of the Hated Pretender is an introductory adventure for 4-6 characters levels 0-1.
Originally published on the Dungeon of Signs blog, it is a short drop-in location-based adventure with a couple of interesting puzzles, a lack of "book" monsters, implacable foes with an obvious weakness, and a very weird roleplaying opportunity.
The new 2020 edition republished by Hydra Collective adds suggested guidance for new Dungeonmasters who grew up with 5th edition and don't know how old-school works.
Stats for both BECMI and 5th edition, and setting neutral (though there are some implied things about the history of the world).
This adventure doesn't have any pending change requests.
fatmessiah has played this adventure and would recommend it.
I've run this twice, and the players had a great time despite one group being absolute novices and one being veterans of the psychic wars. It's got the wonderful weirdness of very early D&D -- the sort that was scraped off in the '80s by the TSR focus on ease-of-play and corporate blandness -- but incorporating 4 decades of subsequent experience in how RPGs should properly work.