Did Krishna ever talk beyond the four caste system?

Question

In this question, I am assuming the meaning of words caste, Varna, class stands for same. Don't consider tribes as same as caste.

Consider the following talks by Krishna in Mahabharata

From Udyoga Parva Section 29

Krishna said, '...Thou must, O Sanjaya, take into thy consideration the division of the four castes and the scheme of respective duties allotted to each. ...'

From the Bhagavad Gita 4.13

"The Holy One said,--'.....The quadruple division of castes was created by me according to the distinction of qualities and duties. ....'

Does Krishna talk about any other statement beyond this four-class system such as out of the caste system, 5th caste etc., anywhere in Mahabharata or any other texts

Answer 1

In Bhagavata Purana,

While Krishna is explaining about the way to worship govardhana hill, he mentions about outcastes.

http://www.vedabase.com/en/sb/10/24/28

After giving the appropriate food to everyone else, including such fallen souls as dogs and dog-eaters, you should give grass to the cows and then present your respectful offerings to Govardhana Hill.

The sanskrit word used in the verse is candala which is an outcaste. Some translate it as outcaste.

http://srimadbhagavatam.org/canto10/chapter24.html

'To act appropriately in respect of everyone, also should be thought of others: fallen souls like dogs and outcasts. After next having given grass to the cows the offerings should be presented to the mountain'

If dog-eater and outcasts are synonymous in the way they are used in scriptures, then even in Bhagavad Gita 5.18 we find Krishna talks about outcasts.

vidyä-vinaya-sampanne brähmaëe gavi hastini suni caiva sva-päke ca paëòitäù sama-darçinaù