At the very least, be sure to back up your Windows files before upgrading. If you are sick of having windows on your system, you can easily remove it and have just OS X on your system.
Just open the Boot Camp Assistant in OS X, select "Create or remove a Windows partition" and click "Continue," and then select the disk with Windows on it, select "Restore to a single Mac OS partition, and click "Continue." If you only have one internal hard drive, you can just click "Restore" to remove Windows.
If you are keeping your current installation of Windows, you do not need to install any updates from Apple to keep your current installation running as it is.The recent security updates for the Mac OS have nothing to do with Boot Camp and should be applied, but you do not need the firmware or driver updates for Windows; however, if you do choose to install them they should not harm anything.In our announcement yesterday we outlined the available updates, but here they are again: Proceed with Windows 7 install after all Mac OS, Apple hardware, and Boot Camp updates have been applied to the system. If you have Windows Vista on your Boot Camp partition and wish to upgrade to Windows 7, keep in mind that in order to do so you must meet a rather stringent requirement.Windows 7 can only be installed as an upgrade from Windows Vista, and not Windows XP, 2000, or Server.For the full and specific list of models supported, read the following Apple Knowledgebase article: Apply all system updates before installing Windows 7 Apple has released a number of support updates for running Windows 7 in Boot Camp, in addition to Boot Camp itself, which include firmware and driver updates for several Macs, and utilities for the Windows install process.
Be sure to install these updates before installing Windows 7, to ensure full compatibility with the Apple hardware.
Once your Windows 10 installation is up and running, Boot Camp 6 will allow you tap into a number of your Mac's normal features USB 3 and USB-C connections, Thunderbolt, your Mac's built-in card slot (if applicable), and your normal Mac keyboard, trackpad, or mouse.
You need support software (drivers) installed with Boot Camp to use Windows 10.
Windows 10 is available from Microsoft as an ISO file and a USB flash drive.
You need an ISO file of the 64-bit version of the Windows 10 installer to install Windows on your Mac.
If your "bitness" matches up and you are ready to upgrade, as with a clean installation of Windows be sure that you apply all applicable software and firmware updates to the Mac OS and Mac hardware before applying the update.