The BSL is compatible with the GPL, so I find it very hard to believe that Apache 2.0 is incompatible.
Source: https://en.wikipedia.org/wiki/Comparison_of_free_and_open-source_software_li...
I believe it is more correct to say Apache 2.0 does not meet Boost requirements to the license in that it is more restrictive than the BSL. In particular, BSL has no requirements similar to those in Apache 2.0 [1] Section 4 item b.
Also, unlike BSL, Apache 2.0 is not compatible with GPLv2, only GPLv3, which is not as popular.
The boilerplate comment that is recommended to be used to apply the license, and the license itself, are significantly longer than those of BSL. I'll remind that this thread has started from someone having difficulty reading and understanding the BSL, and Apache 2.0 is not likely to improve on that.
Irrespective of the merits of the various licences, I would remind everyone that it took us the better part of 2 years last time we changed licences... and Boost has grown immeasurably larger since then. I am emphatically not going to take on that task again, if someone else wants to volunteer, I can only wish them good luck - they will most certainly need it! Best, John. --- This email has been checked for viruses by AVG. http://www.avg.com