First recorded (as a demo) by John Lennon (1968).
Hit B-side single version by The Beatles (1969).
From the wiki: “Written by John Lennon as an anguished love song to his wife, Yoko Ono, Paul McCartney interpreted ‘Don’t Let Me Down’ as a ‘genuine plea’, with Lennon saying to Ono, ‘I’m really stepping out of line on this one. I’m really just letting my vulnerability be seen, so you must not let me down.’ First recorded as a demo by Lennon in 1968, multiple versions of ‘Don’t Let Me Down’ were recorded by the Beatles during the tumultuous Let It Be (née Get Back) recording sessions. The version recorded on 28 January 1969 was released as a B-side to the single ‘Get Back’, recorded the same day.
“The Beatles performed ‘Don’t Let Me Down’ twice during their rooftop concert of 30 January 1969, one of which was included in the Let It Be (1970) film, directed by Michael Lindsay-Hogg. When the ‘Get Back’ project was revisited, Phil Spector dropped ‘Don’t Let Me Down’ from the Let It Be (1970) album. The B-side version of the song was later included on the Beatles’ compilation albums Hey Jude, 1967-1970 and Past Masters Volume 2 and Mono Masters.”
The Beatles, “Don’t Let Me Down” B-side single (1969):
The Beatles, “Don’t Let Me Down” from the Let It Be rooftop performance (1969):