It’s a "Service Replacement," not a "Drop-In." You must change the mineral oil to POE oil. If you don't, the oil won't return to the compressor, causing it to seize within weeks due to lack of lubrication.

R407C has a high temperature glide (~10°F). When a leak occurs, the R32 and R125 components escape faster than the R134a. This is called fractionation. To restore performance, you usually have to recover the entire charge and start fresh with new gas.

It was popular for 5-10 years as an R22 dry-charge replacement. However, now that R410A is also being phased out, most U.S. contractors recommend skipping the patchwork and opting for a full system upgrade to R454B or R32 instead.