Exchange 2016: How many attachments may be in the email?

Have you ever wondered how many files you may attach to an email?
For Microsoft Exchange 2016 (CU6) is 249 (250 MIME parts). And it is an unchangeable parameter. Not so much, isn't it?

MaxBodyPartsTotal
This limit specifies the maximum number of message parts that can be used in a MIME multipart message. The value is 250.
https://technet.microsoft.com/en-us/library/bb397226(v=exchg.150).aspx

In the RFCs I can't find any mention of maximum number of MIME parts or attachments. Also I found information that in Gmail there is no limitation to number of files attached, only message size (300 files was delivered perfectly). Feel free to correct me if I'm wrong.