hi everybody / David,
i have just installed the updraftplus plugin and ran into the same error (Error message: S3 Error: Failed to initialise: Invalid signature type: s3).
adding define(‘UPDRAFTPLUS_S3_OLDLIB’, true); in my wp-config.php fixed the issue.
i still want to use this plugin however on a lot more sites, and i’m afraid that one day this ‘fix’ will no longer work.
is is not possible that the plugin checks which library is needed, and then based on that uses the right library that will work?