Update : the issue is solved by Apple.
The version 2.0.1 of Wakaru went live this morning, but unfortunately some users experienced crashes on launch after the update.
The problem is actually on Apple side ( see http://www.marco.org/2012/07/04/app-store-corrupt-binaries for more details).
Please hold-on on the update until further notice.
If you have made the update, don't delete the app from your device, you will lose your data.
Instead Use the procedure below (procedure adapted from GoodReader app). It seems long but it is straightforward.
- Launch iTunes on a computer to which your iPad is synced.
- Connect your iPad to your computer with a USB cable.
- Right-click on your iPad's name in the left part of iTunes.
- Select "Back Up" from the popup menu.
- Wait for the backup procedure to finish. This will save all your files and settings to backup storage within iTunes.
- Note the "Backup" section in the main part of iTunes window (on the "Summary" page of your iPad). Note the time of the last backup. It should be the current time.
- DO NOT DISCONNECT YOUR IPAD AND DO NOT CLOSE ITUNES UNTIL YOU'RE FULLY DONE!!!
- Select the "Apps" tab in the left part of iTunes.
- Find "Wakaru" app there. Use the search bar at the top of iTunes if you have a lot of apps.
- Delete the app from your iTunes library - right-click the app with a mouse, and select "Delete" in the popup menu.
- Redownload "Wakaru" app back to your iTunes library by "buying" it again using the "iTunes Store" link in iTunes app. Don't worry about double-charging - if you're using the same iTunes account (Apple ID) that was used for the original purchase, you will not be charged twice for the same app.
- Delete Wakaru app from your iPad by tapping and holding its icon on your iPad until it starts to jiggle, then press the small X button in the corner of the app icon.
- Select your connected iPad by left-clicking its name in the left part of iTunes.
- Open the "Apps" page of your connected iPad in iTunes.
- In the "Sync Apps" section find "Wakaru" (use the search bar at the top of the screen). It should be unchecked, because you just deleted it from your iPad.
- Drag the app to the right, to the screenshot of your iPad, and drop it somewhere. This will mark Wakaru app for re-installation.
- Press "Apply" at the bottom of iTunes. This will install the app binary from your iTunes library. Make sure that the app launches correctly. Since it's a fresh installation, there will be no files and settings in the app at this point.
- DO NOT DISCONNECT JUST YET!
- Right-click on your iPad's name in the left part of iTunes
- Select "Restore from Backup" from the popup menu. A confirmation dialog will appear. Make sure that it shows the time of the last backup that you were noting a few steps above.
- Wait for the restore process to finish. This will restore your files and settings from the earlier backup.
- Now you can disconnect your iPad.