We mentioned this when BlackBerry announced it but their program to convert BES 5.0 licenses to BES 10 licenses for free is ending shortly. The program is set to expire at the end of the year and requires you to not only convert the license but also activate a phone on that license for it to become perpetual. The licenses you convert are only temporary until you actually activate them before the end of the year.
It should be interesting to see if BlackBerry ends this promotion or continues it after the end of the year. Check out the details here.
Thanks Dmitri for pointing this out!