It's not possible to send any database query containing the "In" function, receiving an "Invalid get index 'in' (on base: Dictionary)" error.

The problem is caused by line 171 of query.gd:
Filters.IN: filter_str = "in"
Which should instead be:
Filters.IN: filter_str = "In"

Line 90 should also be changed accordingly, from:
"eq", "neq", "lt", "gt", "lte", "gte", "like", "ilike", "Is", "in", "fts", "plfts", "phfts", "wfts":
to:
"eq", "neq", "lt", "gt", "lte", "gte", "like", "ilike", "Is", "In", "fts", "plfts", "phfts", "wfts":

The lowercase in is causing the issue.