For the most part, CTN covers the basics of developing iOS apps. The early episodes are written in Obj-C while the Mac world is moving on to Swift. That said ,the overall concepts remain the same. It should also be noted, that Apple may have changed a few APIs that may have been used in the episodes. In general the episodes build on the concepts on the previous episodes.
Beginning in 2019 I will be expanding the scope of CTN to include fundamental computer science and software engineering concepts in addition to Xcode, Swift and iOS.
If you find CTN useful, I would enjoy seeing an YouTube comment indicating where in the world you are located and why CTN is of interest.
Robert Van Slooten