Perhaps the only significant change is the newer jQuery version. It seems to have some leaks in iframes, meaning that it does not dispose all elements it creates for testing browser features properly. Old IE versions are generally prone to leaks and iframes only make the situation worse. They simply do not dispose properly and there isn't much we can do about this. An option to reduce memory issues is to avoid iframes as much as possible with such old browsers. You can also take a look at this blog post
that shows a reason why IE would leak memory with certain objects that have IDs. Nevertheless, if you can isolate a small sample case that shows the controls that you are having issues with we will look into it.
All the best,
the Telerik team
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