Is it very old ?? (before 2016)If it works, you are not in a hurry and you do not need ultra-fast charge, you can also keep it.Defect of the old I4 is that it is slow if you have to charge 4 batteries together (only 375 mA)Try looking at Xtar chargersThere are endless models both USB and AC poweredI recommend trying a USB because it is more versatile, you can use it in a car, with a solar panel or a powerbank, but you must have a vaido adapter to use it at home connected to the mains (at least 2.4 A)Among the many models see VC4 or VC4S or even better VP4 but as I said there are so many models.If you always want to charge 4 batteries at a speed greater than 0.5A I think you have to go for VP4 or similar.
If it is very old you may have some problems with some new battery formats (especially if you use protected batteries)If you don't want to spend a lot of money, you could settle for 2-slot Xtar versions to charge only lithium batteriesLook at xtar.cc/charger there are all the versions on display.Although I didn't need it (I already have bigger models) this year I wanted to try MC2, MC2S, MC3They are fast and cheap.Edit: I also tried the SC2 version it is very valid.
Both XTAR and Nitecore make some really good chargers. My preference is the Nitecore SC4. If you do not like the automatic charging settings you can manually adjust them.