The Sippey online decryptor has been referenced for years as a working solution. However, as noted on StackExchange, “unfortunately they won’t share the code, and you need to email them to get a password to use that online decryptor”. This approach may still work, but it is not transparent or reliable for ongoing use.
This method can be remarkably efficient—benchmarks show that processing archives via external 7-Zip can be than MATLAB's native unzip function. Many developers create wrapper functions to integrate this capability into their workflows. matlab pcode decoder7z best