bitcoin/bitcoin — pull request #1525 by gavinandresen (2012-06-27 18:16:12+00:00)
Title: Use CTransaction/CBlock version numbers for smoother upgrades

These are planning-ahead change to make future upgrades smoother. See https://gist.github.com/2355445 for full reasoning.

The two changes in this pull are:

1. Treat transactions with a version number greater than 2 as non-standard (don't mine or relay them).

2. Warn the user (via the existing Qt/RPC GetWarnings() mechanism) if the blocks in the blockchain are a new version that this bitcoin doesn't understand.