When a CRX is added to the Chrome web store, Google adds a directory _metadata
to the crx. Older versions of Chrome do not know about this directory (tested on Chro
You can try to unzip the CRX (change the suffix name to ".zip" if needed) and then in chrome: Settings -> Extensions check "Developer mode", choose "load unpacked extension.." and select the extracted folder.
P.S.
I had to rename the folders starting with "_" (underscore) and remove the line
"default_locale":"en",
from the manifest JSON in order for that to work