SN-3143 已核对来源，附原文与上下文。
它能分阶段引入，比如：
It can be phased in, like:
if (blocknumber > 115000)
if (blocknumber > 115000)
maxblocksize = largerlimit
maxblocksize = largerlimit
它能提前很多个版本就写进去，这样等到到达那个区块号、真正生效时，没有它的旧版本早已被淘汰。
It can start being in versions way ahead, so by the time it reaches that block number and goes into effect, the older versions that don't have it are already obsolete.
接近截止区块号时，我能向旧版本发警报，确保它们知道自己务必升级。
When we're near the cutoff block number, I can put an alert to old versions to make sure they know they have to upgrade.
