I don’t think it’s necessary to update the software for current charts. You just need to update the FMS database from Navigraph. Search support for Navigraph. Disclosure, I tried to do this and broke the G1000 software. I am still sorting this out.
It turned out I had to update my version of Flight1tech G1000 Student. It had a bug that crashed it on Navigraph data after a certain rev. Using the latest version fixed it.
Also, I think the G1000 Student update also provides a more recent FMS data release, so you might not even need to buy the Navigraph subscription to get SF Bravo. IDK.