Hi!
I don’t understand why Mikrotik keeps DSA, its insecure (yes, also the 2048bit version), and does not support RSA. Anyway yesterday OpenSSH 7.0 has been released and DSA is not longer supported. So please move to RSA and ECC now - Thx!
see also:
http://it.slashdot.org/story/15/08/11/2340247/openssh-70-released