by t_b_s » Tue Feb 12, 2019 1:30 pm
Bounding boxes (or "data windows") are a relatively old EXR feature, I am quite sure it existed before 2.0.
Not every application necessarily implements the whole feature set of the OpenEXR (or any other) library regardless of what version is used. A feature which exists since 2.0 from 2013 is the ability to write subimages instead of channels ("multipart exr") which gives you the ability to read these selectivly without the need to transfer the whole image. Unfortunately, few renderers actually use this feature so it always makes sense to set up a post render process (e.g. with OpenImageIO) to make huge renders digestible for composting.