Abu Daoud, an Anglican "Christian lving in the Middle East," is discussing the Didache on his blog, Islam and Christianity.
Dating on the Didache, "the Teaching of the Twelve Apostles" is disputed, but the range is somewhere between AD 70 and AD 110. For various reasons, AD 85-100 is probably the most likely time period.
There are many things of interest in the Didache, the first part of which concerns Christian ethics. Among them are instructions about baptism, a call to fast twice weekly, on Wednesdays and Fridays, references to the Eucharist as "sacrifice" along with an allusion to Malachi 1:11 as a prophecy of the Eucharist, and an admonition for Christians to pray the Lord's Prayer three times daily.
However, what Abu Daoud's particular post highlights here has to do with Church order. In the Didache, "apostles" and "prophets" are functionally equivalent. When present, they preside at the Eucharist. In their absence, a bishop presides. All three are "high priests".
There is also the directive quoted in the title of the present piece. We know that Clement of Rome, writing around AD 96, documents the succession of bishops from the apostles as being of apostolic institution. Therefore, it seems likely that the "apostles and prophets" of the Didache are transitional figures in a process which leads to the prevelance of the monarchical episcopate of Ignatius of Antioch, already present in the New Testament in Jerusalem, where James the Just is found presiding with "the elders" (presbyters).
But what of the mandate to the congregation to "appoint for yourselves bishops and deacons"? It is, possibly, a temporary provision, based upon the absence of "prophets and apostles." It is certainly not documented as having continued in the early Church, beyond the role of the community in assenting to, or even selecting, candidats for ordination by a bishop or bishops. At the same time, I wonder if this provides some wiggle room for the acceptance of clergy who have not been ordained by a bishop in apostolic succession, everything else being equal. Since, in virtually all cases, everything else is NOT equal when it comes to faith and practice, such wiggle room would only be available to a body such as the Evangelical Orthodox Church.