As of 1 January 2022, all Medtner's published works are out of copyright worldwide with the exception of Opp 57, 58-60 and the piano quintet that might be in copyright in the USA; however IMSLP's copyright notice indicates that Opp 57, 59 and 60 are probably not in copyright.
In the UK, copyright in a published edition expires 25 years from the end of the year in which the edition was first published. Typographical copyright does not exist in the USA.
In the UK and EU, for recordings that were in copyright on 1 November 2013, protection lasts 70 years from the end of the year in which a recording is published or otherwise made available to the public (e.g. by broadcasting); or for unpublished recordings, 70 years from the end of the year in which it was made. Recordings out of copyright under the previous 50-year rule, i.e., recordings published before 1 November 1963, remain out of copyright. For recordings made before 1 June 1957, whether published or not, copyright in the UK lasts 50 years from the end of the year in which the recording was made.
In Russia, recordings are in copyright for 50 years after the end of the year in which the recording was published or broadcast. This differs from the 70-year rule applied to scores.
The situation is more complicated in the USA. Recordings are generally protected either for life + 70 years or 95 years after creation, but some recordings made before 1972 will be protected by state law until 2067 regardless of their date of origin. Laws in other countries vary widely.
There has been some debate as to whether digital remastering of old recordings can create new copyright. A US court ruled in 2018 that it cannot. This has not been tested in the UK, but a court decision stated that the restoration of old public domain photographs is not worthy of copyright protection.