It can be difficult to get help on the old geometry, as many developers were working with BufferGeometry way before r125. 
When I myself started with three.js at r82, I used Geometry first. But following a tip from Mugen87, I also realized my addon
Addon. Produces almost infinite many time-varying geometries with functions
(and others) as indexed and non-indexed buffer geometry. I differentiated between all three versions in one file by selecting them. This makes it easy to see where there are differences or similarities between the versions. Certainly not an easy read, but possibly helpful to transfer something from BufferGeometry to the old geometry.
Compare for downgrade.
function create()
function morphVertices( time )
function morphFaces( time )
function vertexFaceNumbersHelper( mesh, mode, size, color )
this.update = function ( mode )
