An Interesting Pawn-Break in a Four-Bishops-Ending

Modern correspondence chess is not what it used to be in the seventies of last century. Very little theory (comparing to modern era) and no computers, databases and engines. Just to give you a good example what I mean: The Isaac Boleslavsky's book "Drachenvariante bis Paulsen-System" published by Sportverlag Berlin in 1971 and

Boleslavsky: Drachenvariante bis Paulsen-System

covering such extensive systems of Sicilian Defence like Dragon, Najdorf and Paulsen system in one volume, was just simply A5 format book with less than 300 pages. Try to compare this book with Gufeld & Stesko "Ultimate Dragon" which is focused on Dragon line only and it is published in two volumes of the similar size each.
Well, so if you play correspondence chess today you have to opt for "anti-computer" strategies and to play for ending.
My following post is dedicated to an interesting Bishop endgame with plenty of pawns and all four Bishops on the board. The fact that I won is just a bonus. But there are three interesting motifs which I want to highlight and this is the reason why I publish this ending here.
First, it is a motif of pawn-break. Second motif is gaining the space advantage by restriction and advancing the King into opponent's camp. The last one is a "Zugzwang".
The pawn-break is perhaps the most important part of whole endgame. Once I saw it I became to believe that I could possibly win.
The ending is complex and I did not publish all possible lines which I had analysed, but if you find some interesting improvement of either attack or defence, please make your comment.
Hope you will enjoy as much as I did.