Salaam,
I don't know how well known this is. As far as I am aware, most writing on Sufism and the transition to the New Republic in Turkey does not mention how the tekke managed to continue sort of underground. It is from my review/essay on Kudsi Erguner's book The Journeys of a Sufi Musician published in the latest issue of Bosphorus Review of Books:
"The Sufi ceremonies were forbidden by the government of the New Republic in 1925 and this seems to be the start of a profound cultural change in Turkey with traditional music and Sufism going into decline. However, although Sufism was banned and the
tekke were confiscated by the state, according to Erguner, Sufism still managed to continue in secret to some extent. Those
tekke that weren’t converted into museums, mosques with government-appointed imams or schools were registered by the Ministry of Historic Monuments but remained closed. The confiscated
tekke weren’t well-supervised and Sufis rented them or parts of them and performed their music,
zikr and
sohbet [intimate spiritual conversations] ceremonies in secret. According to Erguner, at one time the whole of the Uzbek
tekke was rented out and the sheikh of the Naqshbandi
tarekat, Sheikh Necmeddin, continued to hold
zikr sessions with several hundreds of men and the sheikh himself went on retreats there lasting several weeks."
There's also some interesting material on the early Whirling Dervish celebrations held in Konya, and much more. If you haven't read the book, read it. I'd also recommend reading everything by Erguner you can find as he has challenging (perhaps uncomfortable for some) and original ideas about Mevlevi Sufism.
Iljas