Here's some more info I found for people interested in what has happened and may happen again.
Block Versions
Version 1 was introduced in the genesis block (January 2009).
Version 2 was introduced in Bitcoin Core 0.7.0 (September 2012) as a soft fork. As described in BIP34, valid version 2 blocks require a block height parameter in the coinbase. Also described in BIP34 are rules for rejecting certain blocks; based on those rules, Bitcoin Core 0.7.0 and later versions began to reject version 2 blocks without the block height in coinbase at block height 224,412 (March 2013) and began to reject new version 1 blocks three weeks later at block height 227,930.
We are here at Version 3 blocks will be introduced when sufficient numbers of miners switch to using Bitcoin Core 0.10.0 and other versions that create version 3 blocks. As described in draft BIP66, this soft fork change requires strict DER encoding for all ECDSA signatures used in transactions appearing in version 3 or later blocks. Transactions that do not use strict DER encoding have been non-standard since Bitcoin Core 0.8.0.
Version 4 blocks will likely be introduced in the near-future as specified in draft BIP62. Possible changes include:
Reject version 4 blocks that include any version 2 transactions that don’t adhere to any of the version 2 transaction rules. These rules are not yet described in this documentation; see BIP62 for details.
A soft fork rollout of version 4 blocks identical to the rollout used for version 3 blocks (described briefly in BIP62 and in more detail in BIP34).
https://bitcoin.org/en/developer-reference#block-headersMake sure to stay up to date and if mining make sure your mining pool stays up to date.
For what i read this effects you if could get invalid transactions that look "real" because they were considered "real" by "outdated" software. (wallets not update with latest QT) This could be bad in a business transaction say you sent someone money and they said it was invalid bad situation.
If your mining you could loss a great portion of blocks which were mined if your pool is on the wrong side or mining the wrong version. Meaning your blocks mined could be nullified. It helps if you have an up-to-date qt wallet to know if those are the blocks from the wrong version but you still loose those blocks meaning pressure your pool to upgrade or switch to one that did.
Thank you forrestv for keeping an eye out for P2Pool and continuing to support development