Reaper 5.20 released... huge update
Reaper has been updated to 5.20 with a huge release log from the 5.18 version:
v5.20 - May 17 2016
+ API: improve MIDI_Sort function [t=174909]
+ Accessibility: improve fader/knob descriptions for VoiceOver and MSAA
+ Accessibility: improve project tabs/docker tabs/various other tabs with VoiceOver
+ Actions: fix certain keys in actions window filter box on OSX [t=175928]
+ Actions: action to set item ends to start of next item only affects selected items [t=93064]
+ Automation: add trim volume envelope, actions to apply to/from trim to volume envelopes
+ Automation: fix inaccuracies reading mute envelopes when stopped [p=1669017]
+ Automation: improve actions to write all envelopes [t=175501]
+ Automation: improve rounding behavior when at the end of square envelope segments [t=169452]
+ CoreAudio: try to normalize samplerates when opening multiple devices
+ CoreAudio: only open one device when using a single default device
+ FX: change default FX resize to down as well as up
+ FX: reduce memory use for plug-ins with large state data
+ JSFX: make @serialize faster and use less memory
+ JSFX: add WigWare Multi-Channel VU Meter
+ JSFX: add midi_delay
+ JSFX: eliminate more constant conditional expressions, improve code generation
+ JSFX: fix match() matching %s at end of string [t=176046]
+ JSFX: send meta-events (beginning with FF) unwrapped via midisend_buf/str (do not treat as sysex)
+ Markers/regions: always encode color as RGB in .csv export [t=176781]
+ Markers/regions: fix cross-platform color translation issue
+ MIDI editor: add mouse modifier to select all later notes of same pitch
+ MIDI editor: add mouse modifier to select all notes in measure (shift+alt+click by default)
+ MIDI editor: add undo points when using velocity edit actions [t=175752]
+ MIDI editor: prevent note edit preview while recording [t=174161]
+ MIDI editor: allow separate selection link to visibility and editability in track list
+ Media items: add undo point when renaming source media
+ Media items: improve handling of zero-length items [t=102921]
+ Media items: fix heavily-looped, resampled items [t=70178]
+ Media items: fix very-zoomed-out peak display on very short looped items
+ Media items: improve stretch marker behavior with pitch shifting and 0ms stretch marker fade time
+ Media items: fix potential for incorrect take FX chasing/small seeks
+ Media items: vary take lane size in order to use all available space [t=93071]
+ Metronome: fix count-in rounding issue [t=173878]
+ Metronome: improve behavior when moving click sources across time signature changes [t=175402]
+ Mixer: fix potential hang when using theme that sets mcp_min_height=0 [t=175196]
+ Mixer: improve action behavior with docked but invisible master mixer
+ Mouse modifiers: change "paint notes or chords" to "paint notes and chords"
+ Notation editor: add MIDI notation editor!
+ Notation editor: handle most mouse and keyboard insert/edit behaviors identically to existing MIDI editor
+ Notation editor: save notation data with project MIDI; notation-specific import/export will come later
+ Notation editor: support single track or continuous scrolling multiple track view
+ Notation editor: support grid spacing (default) or proportional musical note spacing
+ Notation editor: support customizable display quantization
+ Notation editor: support optional automatic triplet detection
+ Notation editor: support inserting and editing arbitrary manual tuplets
+ Notation editor: support some articulation, ornaments, dynamics, pedal, octave notation
+ Notation editor: support lyrics, phrases/slurs
+ Notation editor: support automatic or custom beaming
+ Notation editor: support key signatures, clef changes, transposing instruments
+ Notation editor: support up to 3 voices, option to automatically voice overlapping notes
+ Notation editor: support non-standard accidentals (E sharp, G double-flat, etc)
+ Notation editor: support coloring selected notes or note heads by pitch, media source, velocity, voice
+ Notation editor: support custom note head glyphs per-note or per-pitch
+ Notation editor: optionally bracket tracks by project folder
+ Preferences: fix auto-mute UI disabling [t=175117]
+ Project bay: improve handling of folders when full source media path changes
+ Project bay: preserve source media folders when media is removed and re-added to project
+ Project bay: update source media folders when renaming via media item properties
+ ReaInsert: fix MIDI monitoring latency when stopped
+ ReaPlugs: reduce undo state memory use
+ ReaScript: fix EEL match() matching %s at end of string [t=176046]
+ ReaScript: fix potential memory leak [t=176582]
+ ReaVerb: fix potential crash when switching presets [t=175247]
+ Render: allow render blocksize as low as 4 samples
+ Save as: prompt when overwriting a file saved to a subdirectory [t=174851]
+ Theme: add new master track layouts [p=1671397]
+ Transport: update play button state after various actions which stop playback [t=64343]
+ Undo: fix incorrect history update when using save-as to an existing project [p=1664941]
+ Undo: warn when inconsistencies or errors occur loading undo history
+ VST: add global option, per plug-in compatibility options for ignoring/processing automation notifications
+ VST: show shell plug-in scanning details when performing manual rescan
+ Video: add extensions to allow VST plug-ins access to video
+ Video: support writing multichannel audio to video files using OS X AVAsset encoder
+ Wave: avoid potential wave file reader crash [t=102921]
+ Wave: fix junk being written to unused fields in certain cue chunks
The most important is the Notation Editor. Tomorrow it will be available in repaer.fm for download, but you can download it now from the pre-release repository. Just go to Reaper forum, Pre-Release Discussion sub-forum and there is a sticky thread "
REAPER pre-release builds" wih the link to the "landoleet" page where you will find this new release. Note that despite the forum name, this is now pointing to a final release and not a 'pre' one.