@Tomato42 -- On the other hand, we are very slow to adopt new software because of the difficulties in verifying it against the older. Current CERN recommended OS is CentOS 7, but our software is only certified for SLC (Scientific Linux CERN) 6, so sites which have adopted C7 have to run analysis/Monte Carlo software in SLC6 containers. ISTR there was a glitch in this when it was first tried.