Window 10 upgrade - says Norton 360 will no longer work correctly

I have a Windows/7 64 bit system and am being offered a free upgrade to Windows 10 - however it also warns me that the following apps might not work correctly after the upgrade:

Norton 360.

I am keen to upgrade to Windows 10 but I do not want to be without Norton antivirus.

Q1. Is this true?

Q2. If so what is the nature of the failure to "work correctly"?

Q3. If so does Symantec have a solution?

Q4. Is the solution free?

Q5. If not - how much?