diff --git a/pioreactor/structs.py b/pioreactor/structs.py
index b7d24a76..13a7ec16 100644
--- a/pioreactor/structs.py
+++ b/pioreactor/structs.py
@@ -154,6 +154,10 @@ class CalibrationBase(Struct, tag_field="calibration_type", kw_only=True):
     y: str
     recorded_data: dict[t.Literal["x", "y"], list[X | Y]]
 
+    def __post_init__(self):
+        if len(self.recorded_data["x"]) != len(self.recorded_data["y"]):
+            raise ValueError("Lists in `recorded_data` should have the same lengths")
+
     @property
     def calibration_type(self):
         return self.__struct_config__.tag
@@ -212,6 +216,13 @@ def ipredict(self, y: Y, enforce_bounds=False) -> X:
         roots_ = roots(solve_for_poly).tolist()
         plausible_sols_: list[X] = sorted([real(r) for r in roots_ if (abs(imag(r)) < 1e-10)])
 
+        if len(self.recorded_data["x"]) == 0:
+            from math import inf
+
+            min_X, max_X = -inf, inf
+        else:
+            min_X, max_X = min(self.recorded_data["x"]), max(self.recorded_data["x"])
+
         if len(plausible_sols_) == 0:
             raise exc.NoSolutionsFoundError("No solutions found")
         elif len(plausible_sols_) == 1:
@@ -220,7 +231,6 @@ def ipredict(self, y: Y, enforce_bounds=False) -> X:
             if not enforce_bounds:
                 return sol
 
-            min_X, max_X = min(self.recorded_data["x"]), max(self.recorded_data["x"])
             # if we are here, we let the downstream user decide how to proceed
             if min_X <= sol <= max_X:
                 return sol
diff --git a/pioreactor/tests/test_utils.py b/pioreactor/tests/test_utils.py
index 95a63417..31a24b16 100644
--- a/pioreactor/tests/test_utils.py
+++ b/pioreactor/tests/test_utils.py
@@ -10,6 +10,7 @@
 
 from pioreactor.background_jobs.stirring import start_stirring
 from pioreactor.tests.conftest import capture_requests
+from pioreactor.utils import argextrema
 from pioreactor.utils import callable_stack
 from pioreactor.utils import ClusterJobManager
 from pioreactor.utils import is_pio_job_running
@@ -374,3 +375,8 @@ def test_retrieve_setting(job_manager, job_id):
     job_manager.set_not_running(job_key)
     with pytest.raises(NameError):
         job_manager.get_setting_from_running_job("test_name", "my_setting_int")
+
+
+def test_argextrema_with_empty_lists() -> None:
+    with pytest.raises(ValueError):
+        argextrema([])
diff --git a/pioreactor/utils/__init__.py b/pioreactor/utils/__init__.py
index 620bfce7..54fa6656 100644
--- a/pioreactor/utils/__init__.py
+++ b/pioreactor/utils/__init__.py
@@ -456,6 +456,9 @@ def get_cpu_temperature() -> float:
 
 
 def argextrema(x: Sequence) -> tuple[int, int]:
+    if len(x) == 0:
+        raise ValueError("argextrema() arg is an empty sequence")
+
     min_, max_ = float("inf"), float("-inf")
     argmin_, argmax_ = 0, 0
     for i, value in enumerate(x):
diff --git a/update_scripts/upcoming/cal_active.py b/update_scripts/upcoming/cal_active.py
new file mode 100644
index 00000000..eb1263bf
--- /dev/null
+++ b/update_scripts/upcoming/cal_active.py
@@ -0,0 +1,43 @@
+# -*- coding: utf-8 -*-
+from __future__ import annotations
+
+import json
+import sqlite3
+
+import click
+
+from pioreactor.utils import local_persistent_storage
+
+
+def old_active_calibrations(sql_database: str):
+    try:
+        conn = sqlite3.connect(sql_database)
+    except sqlite3.OperationalError:
+        return
+    cursor = conn.cursor()
+    cursor.execute("SELECT value FROM cache")
+
+    for row in cursor.fetchall():
+        data = json.loads(row[0])
+        yield data
+
+
+@click.command()
+@click.argument("db_location")
+def main(db_location: str) -> None:
+    with local_persistent_storage("active_calibrations") as c:
+        for old_cal in old_active_calibrations(db_location):
+            if "pump" in old_cal["type"]:
+                type_ = old_cal["type"]
+            elif "od" in old_cal["type"]:
+                type_ = "od"
+            else:
+                print(f"Unknown type {old_cal['type']}")
+                continue
+
+            c[type_] = old_cal["name"]
+            print(f"Setting active calibration for {type_} to {old_cal['name']}")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/update_scripts/upcoming/cal_convert.py b/update_scripts/upcoming/cal_convert.py
index 5831be9c..89f62871 100644
--- a/update_scripts/upcoming/cal_convert.py
+++ b/update_scripts/upcoming/cal_convert.py
@@ -63,6 +63,7 @@ def old_calibrations(sql_database: str):
 def main(db_location: str) -> None:
     for old_cal in old_calibrations(db_location):
         try:
+            print(f"Converting {old_cal['name']} to new calibration format.")
             if "pump" in old_cal["type"]:
                 new_cal, device = convert_old_to_new_pump(old_cal)
             elif "od" in old_cal["type"]:
diff --git a/update_scripts/upcoming/update.sh b/update_scripts/upcoming/update.sh
index a704105e..8619dcfc 100644
--- a/update_scripts/upcoming/update.sh
+++ b/update_scripts/upcoming/update.sh
@@ -36,6 +36,9 @@ sudo -u pioreactor python "$SCRIPT_DIR"/cal_convert.py "$STORAGE_DIR"/od_calibra
 sudo -u pioreactor python "$SCRIPT_DIR"/cal_convert.py "$STORAGE_DIR"/pump_calibrations/cache.db
 chown -R pioreactor:pioreactor "$STORAGE_DIR"/calibrations/*/*.yaml
 
+sudo -u pioreactor python "$SCRIPT_DIR"/cal_active.py "$STORAGE_DIR"/current_pump_calibrations/cache.db
+sudo -u pioreactor python "$SCRIPT_DIR"/cal_active.py "$STORAGE_DIR"/current_od_calibrations/cache.db
+
 # if leader
 if [ "$HOSTNAME" = "$LEADER_HOSTNAME" ]; then