Converting PCs from one rules system to another, eg 4e to 5e - I've done mid-campaign conversions before and they have never worked well, even 3e to C&C. Converting always damages the campaign and it tends to fade away pretty fast. As GM I've learned to stick with the current system to the conclusion of the campaign. If I want to use a new system I've learned to start a new campaign with new PCs.
So my advice to GMs would be to stick with your current system, conclude the campaign at a good stopping point, and then start a new one with new PCs & new rules, which can be set in the same world.
Read more: http://www.enworld.org/forum/showthread.php?467764-Converting-characters-recommendations/page2#ixzz3kT54SgXa