04/23/17 Pow Mining "outage"

Hello everyone,

As of 10:09:28 GMT, April 23rd, 2017, the Decred blockchain has experienced an "outage" of most of its PoW mining infrastructure. I refer to this as an outage since the core Decred software continues to work properly, but the PoW mining infrastructure that Decred uses has run into several temporarily show-stopping bugs. In short, PoW mining pool software and client mining software maintainers were not proactively informed about the now-required field, the stake version, and this has led to our consensus daemon, dcrd, rejecting blocks generated using these pieces of software since they are required to set the stake version to 3, despite hard-coding the value to 0. Users who solo mine using the gominer client are unaffected by this problem, but they likely represent a small percentage of the overall hashpower.

There are 2 major components to most actively-mined altcoins, a collection of software that comprises the mining pool and the client mining software that individual miners run on their mining rigs. With Decred, the various mining pool software configurations use the getwork JSON-RPC to get a block header from dcrd, which they then relay to their pool clients. However, the pool software typically makes changes to these headers before they are sent to clients, which in the case of Decred meant zeroing out the stake version field that was added with version 0.7.0. Similarly, mining client software, such as ccminer, zeroed out that same field for the stake version.

Decred's hard fork voting depends directly on this new stake version field incrementing, which is a prerequisite for tallying votes for the new agendas being voted on. As such, we require that the mining pool and mining client software be updated to support non-zero stake versions. Stake version 3 activated as of block 127072, so we need mining pool operators and miners to update their software to support this non-zero stake version.

I have been in touch with the larger pools, coinmine.pl, operated by @feeleep, and suprnova.cc, operated by @ocminer, who helped diagnose the problem. Currently, the following pools have updated their software to properly handle stake version

• yiimp.ccminer.org - must change port from 2252 to 3252
  
• suprnova.cc - must change port from 2252 to 3252
  
• coinmine.pl - no change in settings required
  
• pool.mn - no change in settings required

Once a few percent of the mining power comes back online, new blocks should start to show up on the network.

All miners except those using gominer in solo mode, i.e. not using a pool, must update their mining client software before restarting mining. We recommend turning off your miners until you have an updated binary for your mining client. ccminer has pushed the fix to correctly handle the stake version field to GitHub, so users that are comfortable building from source can update their miners. The binary patch releases that fix this problem are linked below as they become available:

• ccminer - Windows 64-bit, Linux users should pull latest master and use the build script
• sgminer - Windows 32-bit and 64-bit, Linux 32-bit and 64-bit
• claymore - Windows and Linux version 9.2, update port from 3333 to 3343
• gominer - Windows and Linux 64-bit

I will update this announcement as more mining pool software and mining client software fixes occur in the next several hours and days.

UPDATE: As of 0743 GMT+5, approximately 60% of the hashpower has updated their mining clients.