I just got an automated phone call claiming to be Bitmain.  It told me about the new S11 miner that will be available on June 10th and as a valued customer I will be allowed to pre-order up to 50 of them.  There was no mention of the hashrate, and I have no idea if it was really Bitmain calling me, but it did ask me to confirm certain information that only Bitmain or someone who had hacked Bitmain's user database would know...

Yes it is!  Enquire means to 'ask', so enquiries means, at least in this context, 'general questions'.  Inquire means to make a specific or formal investigation.  Isn't English great?