This has been done as Microsoft will be dropping support for anything less than IE11 in January, IE10 and below are missing loads of modern web features that the TGC sites will start using in the future, there are a lot of changes coming in the new year.
We have taken this as the chance to drop support for old browsers, we won't be fixing any bugs on these outdated browsers for any TGC service. It saves a lot of development time if we don't worry about the bad standards support of old IE versions.
Rest assured we will support IE11 and will fix any bugs, as that is the latest IE version on Windows 7 it shouldn't be an issue for anyone, apart from those on corporate machines, but as Microsoft is dropping support soon you should be in store for an upgrade.
Windows 7 Pro, Intel i7 3.8 GHz (Passmark: 9021), 16GB DDR3, NVIDIA GTX 780 4GB Superclocked (Passmark: 8056)