On June 29th, Adobe released the first Service Pack for AEM 6.4. Aside from a minor version bump in the embedded Jackrabbit Oak engine (1.8.2 → 1.8.3, see Changelog here), there are some pretty useful updates in this Service Pack. Highlights include:

• STARTTLS support for the Day CQ Mail service
• Expanded support for color profiles in Assets
• Many OOTB items have been moved from /etc to /conf to really drive the adoption of ConfMgr (check out Nate Yolles’ helpful article if you’re not sure what I’m talking about)
• Various TouchUI fixes, including in the new “cascading dropdown” fields
• Lots of expansion of ARIA (accessibility) features throughout the product
• Several performance fixes

You can find more details in Adobe’s Release Notes, or download the update from Package Share.