All King games, including Pet Rescue Saga, are being updated to a new version and gradually rolled out to everyone. Some things like the bonus games may be temporarily missing.

Here is an extract from a post explaining the change (it is relevant to all games, not just Candy Crush) :

"Hello all,

I would like to give you some information as to why the appearance of the game has changed for some of you.

Traditionally, Flash has been the standard software on which the games are created and run. HTML5 is a newer technology that is faster, more efficient and more secure for you and your devices.

Due to this, a lot of tech firms, including Apple, Microsoft and Mozilla are now phasing out support for Adobe Flash and moving towards other more stable and secure options, namely HTML5.

Here at King we also in the process of moving all our games onto a HTML5 platform.

You can read more about it here:

https://care.king.com/en/blog/article/is-your-browser-ready-for-html5

During this transition certain browsers, e.g Internet Explorer and Safari, may experience temporary or permanent issues in loading the game. We recommend using Google Chrome, Mozilla Firefox or Opera to ensure a smooth, playing experience.

You can download either of these from the following links:

https://www.google.com/chrome/browser/desktop/index.html

http://www.mozilla.com/firefox/upgrade.html

http://www.opera.com/computer

The transition to HTML5 might also mean that certain features will not be available for the time being.

Kind regards,

Johnny"          The original post can be found here