Ok this may look like spam at first, but please listen. Nobody has spoken up on this yet, but something really must be said on this issue.
After every update the BD staff has been advising players to clear both their cookies and they're cache. With all honesty, any company who suggests that you clear your cookies should immediately fire their programmers. This may sound harsh, but I will endevour to elaborate shortly. Suffice to say that, if the programmer knows what a cookie is, then they also know how to clear it from within the program itself. The cache on the other hand is more complex and in some cases this is necessary. I will discuss this briefly, but I'm unaware of any potential fixxes for this issue.
Now why did I say earlier that "With all honesty, any company who suggests that you clear your cookies should immediately fire their programmers." ? Well its a little different depending on what language you are using, but basically setting a cookie is as simple as this in PHP (in most other languages too):
setcookie('test', 'test', 0);
Changing a cookie is done the same way. Deleting a cookie is done like this:
setcookie ('test', '', time() - 3600);
Now, while this can get more complex when they are attempting to roll out a new version of the client, as long as they keep track of what changed (which you should also fire your programmers if they don't keep track of this) it really isn't to hard to change. Basically the solution is to first check if the cookies make sense in the current version of the client and then to either try to repair them, or if they are complete nonsense to just ignore them and replace them with ones that do make sense.
Try these links for more information on cookies:http://www.w3schools.com/JS/js_cookies.asphttp://us.php.net/manual/en/function.setcookie.php
Alright so what is the cache? Well every time you visit a website, your browser downloads the files that make up the website. To make pages load quicker, your browser only downloads files that it thinks have changed since it last downloads them. So the cache is used primarily for making websites faster. Now the problem here, is that sometimes your browser doesn't think the file it downloaded earlier is out of date, when in reality it is. This is pretty common problem with flash games (it happens with java games too sometimes). This is a more difficult problem to solve, but it would be nice if they would look for one.
Alright I hope you learned something here. And I hope you see why I say with all honesty that any company who asks you to clear your cookies just to use their website or play their games, should seriously consider firing their programmers. (cmon guys its not hard to make a web page that will clear just the cookies that your website set)