Softening Shadow Edges in CPU-Rendered Lightmaps

Is there a possibility to denoise in CPU Lightmass like in GPU Lightmass? I can achieve smooth shadow edges with GPU Lightmass in low-resolution lightmaps, but I encounter different issues because it’s in beta. On the other hand, CPU Lightmass generally provides very good lightmaps, but with very crisp shadow edges. Is there a way to solve this without increasing the resolution, through denoising or a different method?
CPU

GPU

The method described here solved my problem.