The OERu is committed to using free and open source software (FOSS) for all our technical infrastructure to the extent possible. We're doing pretty well in living up to that principle, but there are a few crucial technology areas where we have not yet found a sufficiently usable or mature FOSS option. This post identifies those exceptions, as they stand in September 2016. Despite being grateful to have these proprietary applications available to us, we will replace them with FOSS in each case as soon as a viable option is available!