The Imaging Insider tried the new Leica firmware update and they report that everything was okay. No explosions and blue-screns! Check the Insider post for the link to the Leica support page that offers the firmware update binaries. We still don't have a review-cluster for the D-Lux4, but we hope we can get it done when we do our next major review-cluster-a-thon!
RAWsumer reviews at the Compact Reviews Organizer
CANON: G11 S95 G10 G9 S90 SX1is
PANASONIC: LX5 LX3 LX2 FZ50 FZ100 FZ40/FZ45 FZ38/FZ35 FZ28
RICOH: GRD III GRD II GX200
SIGMA: DP2 DP1
NIKON: P7000 P6000
CAMERA DIARIES: Panasonic LX3 Canon G10