Hello,
I don't know how you have installed/updated it in your website but indeed, you're not up to date.
To be sure, I checked the repository but it's not possible to download an old version of the plugin, only the last one is available.
But I would suggest you to check the files via FTP to check if they are not "read only" and maybe upload them manually.
Unfortunately, if the file is read-only, the installation will not be able to update the files and something, without displaying an error or warning message.
Regards,