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Synthesizer V, also referred to as SynthV is a vocal synthesis engine developed by Dreamtonics. A Technical Preview was announced August 8, 2018 and distribution began on August 19, 2018. The full Production Release officially released on December 24, 2018.
Kanru Hua stated on Twitter, the first line of code, the proto-proto libllsm (written in March 2015), eventually became part of Synthesizer V.
Development for Synthesizer V began in 2017. Kanru Hua released a demo using three vocals known tentatively at the time as ENG-F1, JA-F1 & MAN-M1. Synthesizer V made it's first official debut on December 1, 2017.
In February 2018, Kanru Hua posted a listening test to recieve feedback on a new singing pitch model for Synthesizer V. 
In August 2018, Kanru Hua released a "Technical Preview" version of Synthesizer V
On August 20, 2018, Kanru Hua released a survey asking for user feedback on the Technical Preview to be used for future improvements.
On December 24, 2018, Dreamtonics released the Production Release edition of Synthesizer V for sale  with substantial improvements over the Technical Preview edition. 
In March 2019, Kanru Hua announced an application for licensed purchasers of Synthesizer V for early testing of the macOS edition.  This version officially released on March 12, 2019  and all currently released voices were given macOS versions. 
On May 31, 2019 Kanru Hua, with DREAMTONICS, announced in a tweet that he was accepting applications for C++ software engineers to work on the next iteration of Synthesizer V  which later became known as Synthesizer V Release 2 or "SVR2" . This would later on in 2020 become known as Synthesizer V Studio.
Synthesizer V was retired upon release of Synthesizer V Studio in July 2020. While the software and the compatible voice databases were still available for download, functionality may be ceased. By the end of July, nearly every Synthesizer V voice database was updated to Synthesizer V Studio or were made available as Lite voice databases except for Yamine Renri. Renri's update wasn't released until October 2021.
Synthesizer V Editor update (Build 013) - December 27, 2018 
Improved feature: allow playhead's refresh rate to be customized.
Improved feature: add support for multiline lyrics to Input Lyrics dialog.
Bug fix: write permissions for the settings file not being set (Windows).
Bug fix: lowercase "" rests in UST files are loaded as notes.
Bug fix: incomplete loading of parameters from VSQX 3/4 files.
Bug fix: fix some mistakes in Korean and Japanese translations.
Bug fix: (Japanese) ふ and フ are mis-converted to hu. Note: this is not an issue with the databases but the configuration files bundled with the editor.
"Additional notes: Build 013 has been uploaded to the download servers for en, jp, zh-tw. zh-cn will updated later."
Synthesizer V Editor Update (Build 014) - January 4, 2019 
New feature: Magnifier.
New feature: Detachable Note Properties panel.
New feature: Keybindings for piano roll navigation.
New feature: Read/write Midi lyrics.
Synthesizer V Editor Update (Build 015) - January 10, 2019 
New feature: Plays the pitch when creating notes.
New feature: Extended range for loudness parameter.
New feature: mp3 to wav conversion option for importing instrumentals.
Synthesizer V Editor Update (Build 016) - March 12, 2019 
New feature: macOS support (10.11 +)
New feature make mouse behaviors configurable for note creation / editing.
New feature: commands for play / loop selection.
Improved feature: remove invalid characters in the output path.
Improved feature: notify the user before overwriting presets.
Improved feature: press Enter on the selected note to edit lyrics.
Improved feature: use project name as the default for rendering results.
Improved feature: remove non-existing files from recently opened files.
Improved feature: add save/don't save options to quit confirmation dialog.
Bug fix: crashes when switching tracks on-the-fly from Track Manager.
Synthesizer V Editor Update (Build 017) - May 2, 2019 
Improved feature: better performance when importing midi files with excessive BPM events.
Bug fix: the engine does not properly implement syllable onset property for plosives and affricates.
Users will notice that “syllable onset” property becomes much easier to control after this update.
Bug fix: time signature can not be modified at some bars 16.
Bug fix: recently opened files list is not updated when opening legacy project files (.json)
Bug fix: Phoneme Viewer is empty (macOS)
Synthesizer V Editor Update (Build 018) - September 1, 2019 
Bug fix: broken file binding (.s5p) on Windows 24.
Bug fix: high frequency chirp noises in voiced vocals.
Bug fix: glitches and waveform discontinuities in unvoiced vocals.
Other: link against the latest libcurl4 on Linux to fix dependency issues.
"A mistake was found in the macOS package configuration that caused the editor unable to load Chinese voices. The repackaged macOS version has been uploaded as of Sept. 4, 2019."