diff --git a/pyproject.toml b/pyproject.toml
index a9427339..286aa2c6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -51,10 +51,10 @@ gfviz = ["jinja2", "fastapi", "shapely", "natsort"]
 klayout = ["klayout", "pyvis<=0.3.2", "vlsir", "vlsirtools", "gitpython"]
 luminescent = ["luminescent>=0.2.12,<4.1.0", "sortedcontainers"]
 maintainer = ["mypy", "tbump", "towncrier"]
-meow = ["meow-sim>=0.15", "sax~=0.17.0", "tidy3d~=2.11.1"]
+meow = ["meow-sim>=0.15", "sax>=0.17,<0.19", "tidy3d~=2.11.1"]
 meshwell = ["shapely", "meshwell~=2.1.1"]
 path_length_analysis = ["bokeh", "numba", "shapely"]
-sax = ["sax~=0.17.0"]
+sax = ["sax>=0.17,<0.19"]
 schematic = ["bokeh", "ipywidgets", "natsort"]
 tidy3d = ["tidy3d~=2.11.1", "gdstk", "pytz"]  # pin max version because tidy3d often introduces breaking API changes across minor releases
 vlsir = ["vlsir", "vlsirtools"]