Before attempting any download:
Yes. Firmware updates are cumulative. Version 2.1.3 includes all improvements from 2.0.9, 2.1.0, 2.1.1, and 2.1.2. No intermediate updates are required.
For users in the United States, the official download page is often:
https://www.usa.canon.com/support/p/eos-5d-mark-ii
Always re-verify that the page’s URL contains canon.com. canon 5d mark ii firmware update 213 download updated
Canon has removed the 5D Mark II from active support pages, but the official file remains available on their regional servers. Do not download firmware from third-party forums.
Official Download Links (Canon USA):
If the links above do not work in your region, navigate to Canon USA's support site > EOS 5D Mark II > Drivers & Downloads > Firmware.
No. Magic Lantern is an unofficial open-source firmware add-on. To install Magic Lantern, you actually need to keep your camera on an older firmware (usually 2.1.2 or earlier). The 2.1.3 update is not compatible with Magic Lantern. If you use Magic Lantern, do not install 2.1.3. Before attempting any download:
This process takes about 4–5 minutes. Do not touch any buttons or turn off the camera while the update is in progress.