“Sadyomukti is the processless immediate experience of Brahman, spaceless and timeless, on account of one's habituation to the non-dual knowledge of the Self. It is given to a very few to realise Brahman in this way, for most of the aspirants cannot proceed with their meditations without some kind of objective content in their consciousness. The meditation and the control of the Prana reaches a pinnacle that only a very few Sadhakas can realise.
In Krama Mukti, the liberated souls think and work through the higher thought of the spiritual nature, not through the mind and sense-organs of the lower nature. They breathe the universal life and exist as partakers of the joy of the Master of the universe. They have the unceasing immediacy of the consciousness of everything, an awareness of the inmost objective essences of the complete universe. Their experiences are, no doubt, objective, they being not identical with the Absolute, but they can have an entire knowledge of the universe through self-identification with anything, at any time”. In other words, they get rid of the gross body and use subtle their subtle and causal bodies.
These states are achieved through the Ashtanga Yoga of meditation and control of Praana. This is outlined by Bhattathri in this Sloka 10.
One who is desireless of visiting the other heavenly worlds, gives up (through his Aagyaa chakra) his gross body as well as the subtle bodies and merges in Thee. The one who desires to visit the heavenly regions before attaining liberation, goes out through the orifice in the crown of the head ( the Brahmarandhra)
Meaning of the Sanskrit Words
लिङ्ग-देहम्-अपि - even the subtle body
सन्त्यजन्-अथ: - giving up, then
लीयते - merges
त्वयि परे - in Thee, the Supreme Brahman
निराग्रह: - the one who is desireless
ऊर्ध्व-लोक-कुतुकी तु - but the one who desires to go to higher spiritual worlds
मूर्धत: - through the orifice in the head ( Brahmarandhra)