What started out as a simple GUI update turned into pretty much a complete rewrite. As such this version is not backwards compatible with previous versions and none of your old data will work. If you really need your old data contact me and I might be able to manually convert the exported data to be compatible with the new version, but I haven't tried this and it might not be feasible. Also I recommend you uninstall the old version before installing the new one, although it will probably work fine either way.
Change log:
General
Complete UI rewrite using OnsenUI instead of jQuery mobile
Default/home screen is now statistics
Added collapsible side bar menu
Added context responsive buttons
Format of locale files has been improved - translations need to be updated for new version
Updated README.md
Added screenshots
User guide updates
Goals & Statistics
Added tracking of other nutriments - calories, protein, carbs, fat, sugar, salt
You can scroll the top bar of the statistics screen to see consumption of all nutriments
Added goals for all nutriments
Individual goals can be set for each day of the week
Setting date range to 1 week changes to bar chart view
Added more chart colours
Settings
Theme changes are applied instantly
Screen transition animations can be turned off (might improve performance on some devices)
Diary meal names are now customisable and up to 7 can be used
Diary
Much improved date picker and buttons (removed swipe to change date)
Weight can now be recorded on the diary screen or the statistics screen rather than in settings
Added quick add to diary (tap and hold on a diary heading to enable)
Individual lists for each meal
Food list
Brand can now be added to food items
If a scanned product isn't in the Open Food Facts database you can now add it from within Waistline - with camera support too!
Added ability to search Open Food Facts database on food list screen
Added multi-add to food list, removed single add
List can be filtered by product or brand name when typing in the search box