Year Four has a hardcore amount of funk and not particularly in a good way. It has a strange off-putting flavor that I'd consider a flaw. I think the airlock ran dry for a while during this year and the beer developed some acetic acid-based compounds. I also suspect the yeast I added in Year Three just wasn't a good fight and didn't play well with brett. It might improve with some time in the bottle and I'm not in a hurry to drink them so I'll just have to see what develops.
I pitched some WY 1214 into the solera with the fresh wort but after how Year Four turned out I am not very optimistic that Year Five will be free from the awfulness of Year Four. That might make Year Five the last year of this rendition of the solera and I will start a new one. It's often said that sometimes dumping a sour beer is part of the process. I'd hate for the solera to meet that fate but I am also not about to drink six gallons of unpleasant beer.