SiaCoin 1.3.0v RC is out.. Big improvements.

This release has several significant changes. Full release notes will be available when v1.3.0 is fully released, but here are some highlights:

Online file repair. In previous versions of Sia (including v1.2.2), if you deleted your file from your local machine after uploading, it would be unable to restore redundancy, and so as hosts went offline the file would become increasingly unstable, and eventually you would be unable to download it. As of v1.3.0, when your redundancy drops the file will be repaired, even if you don't have the file saved locally anymore. Faster initial blockchain download. When you first start Sia, you have to download and verify the whole blockchain. This usually takes several hours. This release has an update which more than doubles the speed of blockchain download, cutting in half the amount of time you need to wait. Support for using the same wallet on multiple machines. Previous versions had a wallet which could only be used on one machine. If you used the same wallet on multiple machines, it would often look like your coins were missing or even had been stolen. We still don't recommend that you use the same wallet across multiple machines (for any cryptocurrency - it's bad for both security and privacy), however the wallet will now correctly display your full balance on both machines.

Substantially improved transaction propagation. Prior to this release, the transaction pool was capped to a very small size (due to performance bottlenecks), and if transaction pools started to fill up, transactions could stop propagating across the network. As of this release, the transaction pool is larger, has a proper fee market, and has several other modifications that mean it will run better. The ultimate result here is that when you send money on the network, you can expect it to get into a block, even during times of high traffic. A second result is that, generally speaking, transaction fees will be a lot lower than they used to be.

A hardfork for our difficulty adjustment algorithm. Sia's difficulty adjustment algorithm was previously unstable, and a relatively constant hashrate meant that this was okay. A sudden spike or drop in hashrate though is really *bad, and the current difficulty adjustment algorithm handles it poorly. There is a new difficulty adjustment algorithm that adjusts the difficulty every block, and can respond much more effectively to sudden dramatic changes in hashrate. The new difficulty adjustment algorithm has a second property - it keeps the average block time at 10 minutes, even when the hashrate is changing rapidly. **To the best of my knowledge, this is a property that doesn't exist in any other blockchain. **For users, the main result is that when you set your file contracts to last 12 weeks, they will actually last for exactly 12 weeks. For miners, the new hardfork means that rather than having big difficulty spikes or drops once every 500 blocks, the difficulty will change in much smaller increments every block.

A new field was introduced in the 'Host' tab of the UI - 'Conversion Rate'. This was added to help hosts pick prices. Your conversion rate is the chance that a renter who is forming contracts will pick you to be one of their hosts. If it is '1%', this means that you'll get a contract once for every 100 renters who join the network. You can improve your conversion rate by lowering your price, increasing your uptime, or by having been a host for greater than 6 weeks.

Like with every release, we have introduced a number of performance and stability upgrades. It's still an early product, and sometimes acts like one, but every release we are making big steps towards a product that is ready for mass adoption.