Hi @kichikawa_2913,
Sorry, this is actually expected. When we release our products, they include the extensions that were released at the time of the product release. In this case, I released this version of InedoCore after we did the product release.
If you look at our documentation for upgrading your docker image, the command includes --volumes-from=proget-old. This will auto migrate the previous volumes created from the previous version of ProGet and that will keep the updated extension (as long as the previous extensions is newer than the included extension version).
Also, in Administration -> Advanced Settings, you can change Extensions.ExtensionsPath to a mapped path and that will also do the same thing (if the version in this directory is newer than the included) and give you easier access to the extension files.
Thanks,
Rich