Lots of people upgrade to electronic triggering, where the old, original coil is still used for the spark. I prefer to replace the entire system with a brand new magneto / coil.
I've converted numerous old cast iron (and aluminum) block Briggs engines over to modern electronic coils.
Since the older bolt pattern (for mounting the coil) is different, new mounting slots need to be machined into the new-style coil. Using a milling machine, I mill mounting slots in a new electronic coil.
The older engines have the opposite polarity on the flywheel magnets, and will not allow the new-type coil to fire. So, the flywheel also has to be changed. I always swap to a cast iron version.