do I really have to delete and resync everytime I update to a new wallet version? Cause it usually takes me overnight to resync the wallet.

We just released NavCoin v4.0.1.

This new version fixes a critical block validation issue which led to network incongruences between nodes on the last days.

EVERY 4.0 user should update to this version immediately.

Downloads available at:

http://navcoin.org/downloads/

INSTRUCTIONS TO UPDATE

1. Backup your wallet.
2. Close NavCoin Core if it is open.
3. Remove the folders 'chainstate' and 'blocks' from:
      WINDOWS ->  C:/Users//AppData/Roaming/NavCoin4/
      MAC -> ~/Library/Application Support/NavCoin2
      LINUX -> ~/.NavCoin2/
4. Download new version, install and run.

Thanks!