Zcash 1.0.15 is now available.
Most of this release was focused on Overwinter code that will be tested throughout the comings weeks in testnet. Overwinter will activate on testnet at block height 207500. If all testing and auditing goes well, an activation block height for main net will be set in the next release, 1.1.0.
Aside from Overwinter, 1.0.15 implements a new experimental feature z_mergetoaddress.
More details: New Release: 1.0.15 - Electric Coin Company