It is very unlikely that this work is public domain in the EU, or in any country where the copyright term is life-plus-70 years. However, it is in the public domain in Canada (where IMSLP is hosted) and other countries where the term is life-plus-50 years (such as China, Japan, Korea and many others worldwide). As this work was first published before 1926 or failed to meet notice or renewal requirements to secure statutory copyright with no "restoration" under the GATT amendments, it is very likely to be public domain in the USA as well.
|First Publication||1925 – Vienna: Universal Edition / Wiener Philharmonischer Verlag|
|Genre Categories||; ;; ; ;|
|Work Title||String Sextet|
|Opus/Catalogue NumberOp./Cat. No.||Op.25|
|I-Catalogue NumberI-Cat. No.||IEK 10|
|First Publication.||1925 – Vienna: Universal Edition / Wiener Philharmonischer Verlag|
|Dedication||Dem Andenken der Jahre 1918-1919|
|Composer Time PeriodComp. Period||Early 20th century|
|Piece Style||Early 20th century|
|Instrumentation||2 violins, 2 violas, 2 cellos|
Key is A minor and composition dates are 1918-9 according to.
Renewed in 1953 (catalog of c.e., 1953, p.957.)
There is also a Musik, Op.25a, for string orchestra that could be an arrangement of this work in full or in part and is also listed at UE's website.