Submerge 3.7

- Ready for macOS Big Sur.
- New icon.
- FFmpeg version 4.3.1.
- Fixed a rare bug where the second line of subtitles wouldn't render on export.
- Other minor fixes and many UI tweaks.

Submerge 3.6.2

- Fixed export bug for users on macOS Sierra and High Sierra.
- This will be the last version supporting macOS Sierra and High Sierra.

Submerge 3.6.1

- Support for reading YouTube SubViewer subtitles (.sbv) files.
- Fixed a bug affecting portrait mode movies.

Submerge 3.6

- Finally works on macOS Catalina. Phew! No more black movies with subtitles only :-)
- Removed some legacy expport presets.

Submerge 3.5.3

- Fixed a bug that could clip automatically wrapped subtitle lines.