51% of the hashrate mining power is, now, allocated to a new version of
blocks.2017-07-17 20:24:49 UpdateTip: new best=0000000000000000007df6d6851fd8b104b02ed9173cb14202aee5fa66c96443 height=476271 version=0x20000010 log2_work=86.775998 tx=239933248 date='2017-07-17 20:22:23' progress=0.999998 cache=86.8MiB(19448tx) warning='51 of last 100 blocks have unexpected version'
Now,
Pool mining software (like P2Pool server) and Bitcoin Core demand to the owner to upgrade the software (if needed).
It's an
automated alert when more than 50% of the last 100 blocks are mined with an other version of Block.
Be prepared to the newbies questions when they start her wallets ...

2017-07-17 20:38:41 UpdateTip: new best=00000000000000000151077e3d4e0601354286a3cbe4d67dedde7d26e1b317d3 height=476272 version=0x20000010 log2_work=86.776035 tx=239935204 date='2017-07-17 20:35:40' progress=0.999998 cache=21.2MiB(7067tx) warning='52 of last 100 blocks have unexpected version'
52%