3.5.x to 3.6.x differences in styles?
 

I have a 3.5.4 style I made that someone wants converted to 3.6.x but I have not upgraded yet. Is it possible for me to convert the style for 3.6 without upgrading my own forum? Thanks.

not really. it's not the easiest upgrade to do as there are a lot of template changes and unless you have that version installed it will be very difficult to make sure that you get all the changes. If you don't already have one, install a 3.6.x test board either on localhost or on your server but make sure that it is behind htaccess and import the style into there to make the changes.

I've done this for one of my styles and it took me days.
This is realy hard and you also need to create new images for the multi quote for example etc...

Have fun :D

Would it just be easier to do it on his server and essentially re-write the mod and make some new buttons for it?

Its easier to make it on his 3.6.x installation cause then you only need to make the images and add your changes.
If you do it on yours you cannot check all things and you have to update many many templates.

What style are you talking about? Do you have a link to see the original style for 3.5.x?