Took me a little while, but I figured out how to download my free replacement copy of BKC IV from Wargame Vault.
Kudos to Pendraken for stating their plan to address the BKC III debacle, and actually following through, at least with the pdf version. I haven't received my replacement BKC IV hard copy yet, but as of now I don't have any reason to suspect I won't.
As you can perhaps deduce from the previous paragraph, I am not one of these "fanboys" who is willing to give anyone any kind of a pass on quality, commitment, etc., or be beguiled just by shiny new stuff. I started the following thread back on 27 April 2017, very shortly after BKC III came out, and actually took a look at it: TMP link
It took me a bit to find it using TMP's search "feature", but I finally did, and I went through it quickly, looking at BKC IV:
1. The term "Reaction" is far less prevalent in BKC IV, it appears the term is now "Opportunity Fire". It does appear it can occur in both the Initiative and Command phases. As I said in my previous BKC III thread, will have to actually play to see how it works.
2. In BKC III, there were no longer separate FACs. FOs, previously called FAOs, requested both air and artillery. Separate FACs and FAOs are back, so there is a delineation between a nation's artillery support doctrine/ability and their air support doctrine/ability.
3. I, and some others, noted several issues with the army lists. Almost all appear to have been addressed/fixed. One that didn't is there is only one entry for "Elephant/Ferdinand". It has the "Notes/Abilities" of "No Machine Guns". Seems like this should have been two different entries, with only the Ferdinand saying "No Machine Guns". Can address with a scenario house rule I suppose.
4. Field defenses have costs listed for them again.
5. Breakpoint is back to being based on the number of units a side started with and lost, instead of points.
6. The .pdf copy does not include a QRS, you have to go to the Pendraken forum to get it. It is already there, along with 4 other docs: General Optional Rules, Off Table Artillery, Deployment & Formations, and Weather & Terrain. One issue, for me at least: the direct hyperlink in my pdf copy to the Pendraken forum didn't work; however, the link to the main Pendraken site an inch above it did, so I was able to get to the forum.
7. One last note, related to the hyperlink issue above: before trying the link to the main Pendraken site, I tried to cut & paste the direct URL to the Pendraken forum into my browser (Chrome). This didn't work either. I believe this is a .pdf issue/feature, as I also wasn't able to cut & paste example text out of it into this thread above. A copyright protection I suppose, but very annoying when you're trying to do something like this thread, or make your own Army List spreadsheets.
Still, to reiterate what I said above, Bravo Zulu to Pendraken following through on BKC IV. Hope to play a game sometime soon!