From 9.20 to 15.12 it was 5 years (2010-11-18 to 2015-11-19).
SDK updates are at http://7-zip.org/download.html and http://7-zip.org/sdk.html
SDK updates are at http://7-zip.org/download.html or http://7-zip.org/sdk.html
Updates are at http://7-zip.org/download.html
Would be nice to have this on the user interface, anyway.
Why don't you use a Phyton module to read/extract 7z? py7zlib, libarchive, pyunpack..... https://www.google.com/search?q=python+7z
Why don't you use a Phyton module to read/extract 7z? py7zlib, libarchive, pyunpack..... https://www.google.com.br/search?q=python+7z
You use 7z to extract zip, why don't you use 7z to extract 7z?