Correct. It's a minor upgrade for the testnet. The new version is not compatible with older versions.

Upgrade infos

• Remove previous version

• Install new version

Some changes in testnet version 0.4.0a

• Initial resolution to address collision issue
• Improved block processing logic (for faster syncing over network)
• New peer selection code (for more reliable syncing over network)
• Added ability to snapshot highest round, e.g. --snapshot=highest
• Added optional API rate limiting (for /api and /peer)
• Support for uptime snapshotting