this v0.6.0 version of gtfsdb has been running with SQLAlchemy = 1.3.22 for quite some time
next release (early 2024) will target SQLAlchemy = 1.4.5 (or maybe later 1.x.x), along with incremental improvements
a future release (late 2024 / beyond) will look to move to SQLAlchemy = 2.x, which appears to be a big lift