December's Alicante News contains a useful summary of recent changes to the Invalidation Guidelines.  Some of these are procedural, but there are some meaty substantive changes too.  One is the removal of references to "déjà vu", as lacking basis in case law - surprisingly, since the General Court use precisely that term in Case T-666/11 (the "domestic cat" case - still not available in English), and since it was the Commission's original synonym for the "overall impression" test (see the 1993 Proposal at Art 6, p12).  Anyway, the analysis is concise and worthy of a careful read.