The phrase "until superseded" is a perfectly acceptable phrase in written English.
You can use it when you want to indicate that something will remain in effect until something else takes its place. For example: "The old policy will remain in effect until superseded by the new policy."
Incorporated as a borough in 1851, Auckland remained the capital until superseded by the city of Wellington in 1865.
These served as the backbone of Britain's nuclear deterrent until superseded by Polaris-missile-equipped nuclear submarines in the 1970s.
Because of the inherent advantage of RAM, core memory was the principal form of main memory until superseded by semiconductor memory in the late 1960s.
Originally it accompanied plainchant (Gregorian chant) in churches; from the 18th century, until superseded by brass basses in the 19th century, it was a standard wind bass in military bands.
The backstop will endure indefinitely, unless and until superseded by another agreement, save in the extreme and unlikely event that in future negotiations the EU acts in bad faith in rejecting the UK's demands.
L. 92 516 effective at the close of Oct. 21, 1972, except if regulations are necessary for the implementation of any provision that becomes effective on Oct. 21, 1972, and continuation in effect of subchapter I of chapter 6 of Title 7, and regulations thereunder, relating to the control of economic poisons, as in existence prior to Oct. 21, 1972, until superseded by provisions of Pub.
The Knickerbocker Ice Company, which began in 1831, did not close until 1926, superseded by refrigeration.
It remained in the Russian repertory for many years until being superseded, in Soviet times, by a version with new choreography and music.
After going close to reaching the 1974 and 1990 tournaments, Trinidad became the smallest nation to qualify for a World Cup, until Iceland superseded them last year.
The precedent in experimental design established by such studies may represent the most promising intermediary in T. cruzi population genetics until imminently superseded by comparative population genomics.
It was widely used until it was superseded in the next decade by Richard Trevithick's more efficient high-pressure engine.
