The document provides release notes for ArcSight ESM version 5.5. Key updates in this release include new pre-persistence rule type, ability to view event priority ratings, case-sensitive list options, report compression, new variable functions, Oracle 11.2.0.3 support, and supported upgrade paths from ESM 5.0 SP2 Patch 4 or ESM 5.2 Patch 2. The release notes also outline fixed and open issues for various ArcSight components.