Currently the updated version of BD is available from GOG and the Larian Vault
, and should be available soon from Steam. There are at least a couple other digital distributors who have the original download version, which is the same as the latest disk version. There may be a patch; the original digital distributions were handled by the publisher, Focus, who may need to be involved in any updates.
There were no problems with the source code for BD, so none of the fixes or changes in the disk version patches were lost.