Reprinted from TidBITS by permission; reuse governed by Creative Commons license BY-NC-ND 3.0. TidBITS has offered years of thoughtful commentary on Apple and Internet topics. For free email subscriptions and access to the entire TidBITS archive, visit http://www.tidbits.com/ OS X Server 5.1 Agen G. N. Schmitz Apple has released [1]OS X Server 5.1, which has been updated for compatibility with OS X 10.11.4 El Capitan (see '[2]OS X 10.11.4 Improves Notes, iBooks, and Live Photo Support,' 21 March 2016). In fact, OS X Server 5.1 now requires 10.11.4 El Capitan, and previous versions of OS X Server won't work on 10.11.4 El Capitan, so you'll need to make sure to make both updates. The release also adds support for TLS 1.2 (Transport Layer Security), adds support for the new Education features in iOS 9.3 (see '[3]iOS 9.3 Works the Night Shift, Protects Notes, and More,' 21 March 2016), adds new restrictions to the Profile Manager, and brings performance optimizations for iCloud data caching. According to this [4]Apple security note, the update also addresses an issue in Time Machine server that neglected to warn administrators if permissions were ignored when performing a server backup and patches a file access issue that existed in Apache with .DS_Store and .htaccess files. ($19.99 new, free update, 186 MB, [5]release notes, 10.11.4+) References 1. https://itunes.apple.com/us/app/os-x-server/id883878097?mt=12&at=10l5PW 2. http://tidbits.com/article/16341 3. http://tidbits.com/article/16329 4. https://support.apple.com/en-us/HT206173 5. https://support.apple.com/en-us/HT206145 .