South Korean presidential spokesman Cheon Ho-sun said the Taliban will release 19 Christian aid workers "on the condition that South Korea withdraws troops by the end of year and South Korea suspends missionary work in Afghanistan." However, it sounds unlikely that the Taliban will wait until the end of the year to free the hostages.
The Associated Press notes that the agreement may not be as shocking as it sounds: "South Korea has already said it planned to withdraw its troops by the end of the year. Some 200 South Korean soldiers have been deployed in Afghanistan for reconstruction efforts, not combat." Similarly, the Koreans held by the Taliban probably wouldn't have been affected by a ban on "missionary work in Afghanistan" since the church that sent them has repeatedly insisted that the hostages are aid workers, not missionaries.
The Koreans have been held for a biblically resonant 40 days. Two have been killed, two others released.
The Associated Press will continue publishing updates from Afghanistan and Seoul, and I'll update this blog post as more details are available.