There's one more breaking change that I did not find documented anywhere.
For our theme we had to change:
var templates = require('templates.js'); templates.registerHelper('generateCategoryBorder', helpers.generateCategoryBorder);
var Benchpress = require('benchpressjs'); Benchpress.registerHelper('generateCategoryBorder', helpers.generateCategoryBorder);
Not a big deal but some folks might struggle to see why their template helpers don't work on server side.