Transitioning from previous versions of LVM to LVM 1.0.8 should be fairly painless. We have come up with a method to read in PV version 1 metadata (LVM 0.9.1 Beta7 and earlier) as well as PV version 2 metadata (LVM 0.9.1 Beta8 and LVM 1.0).
Warning: New PVs initialized with LVM 1.0.8 are created with the PV version 1 on-disk structure. This means that LVM 0.9.1 Beta8 and LVM 1.0 cannot read or use PVs created with 1.0.8.