I can't guess on coffee grounds.
Problems on your site can only be solved by yourself.
There may be problems with updating WordPress.
It may be incompatible with another plugin or with a new version of the theme.
Why aren't you updating the plugin? You're disrupting your site yourself.
Well I understand how it can be frustrating when you think you know what you want and people try to fix things for you or help you contrary to the parameters you set. You told us an old version and we jump straight to the new. BUT, I think especially in a free community like this where we aren't the authors of the software and you don't have any kind of support contract or motive to dig around in old things without cause, that people aren't going to be as willing to take time to help you if you insist on using old versions of a software. There may be cosmetic things you liked about an older version, but there are countless reasons to choose to update - including security related fixes, and that there may be bug fixes or compatibility issues such as what you are probably running into now. If it were me, and I for some reason was very stubborn about a feature from an old version (like user interface) then I would get the versions that were different and compare them and maybe there might be simple things that could be ported from the old version you like to the new, such as copying the css contents if it was just a matter of colors or fonts or something. However if it is structural or changed in the layout and way things work then in that case it's either a lost cause, or you better learn how to program (or, pay the authors and request the features). Good luck!
Well, if you can't or didn't want to help me, then why are you wasting your time on a pointless scribble that you can't guess on coffee grounds, and also that you are not the authors of the plugin and I need to learn how to program. Don't want to help or don't know? ok, no problem then don't answer guys. I posted a question in the yoast discussion thread, hoping someone else has had a similar situation, this is not a separate thread for version 20 only. Classic flood guys.