Issue #1918820 by neclimdul, typhonius, girishmuraly, pwolanin | 0x534B41: Fixed HTTP header date formats to follow RFC 7231 rather than RFC 1123.
Issue #863594 by David_Rothstein, smussbach, mbrett5062: Fixed Strange first paragraph in the installer database error message.
Issue #1069152 by droplet, alexandrezia, Mixologic, jhedstrom, David_Rothstein | ogi: Fixed Throbber in textfield is misaligned when browser hardware acceleration enabled (followup for Bartik RTL styling).
Issue #1338966 by geerlingguy, loganfsmyth, lokapujya: Fixed Introduce _rdf_mapping_load_multiple to reduce queries.
Issue #393538 by Liam Morland, valthebald, dmitrig01, David_Rothstein: Document that check_plain() can issue PHP messages on invalid UTF-8 input.
Issue #2310415 by cilefen, ednawig, TravisCarden: Fixed run-tests.sh does not handle the error when invalid test groups/classes are specified.
Issue #393538 followup by David_Rothstein: Fixed code style error in check_plain() documentation.