With the latest beta, labels do not work for me.
With the following code:
\definelabel[Q]
\starttext
Label: \Q[abc]
Label: see \in[abc].
Reference: \reference[def]{2}
Reference: see \in[def].
\stoptext
I get:
and the log states:
references > unknown reference '[][abc]'
while with tl18, I get the expected:
--
Rik