diff --git a/algorithms/pir/install.sh b/algorithms/pir/install.sh
index f11f5b21..d3454dfd 100644
--- a/algorithms/pir/install.sh
+++ b/algorithms/pir/install.sh
@@ -1,2 +1,2 @@
 #!/bin/bash
-pip install "git+https://github.com/Qazi-pk/physics-engine.git@v3.4.1"
+pip install "git+https://github.com/Qazi-pk/physics-engine.git@v3.5"
diff --git a/experiment/methods/pir/regressor.py b/experiment/methods/pir/regressor.py
index 960c5d6c..3993db91 100644
--- a/experiment/methods/pir/regressor.py
+++ b/experiment/methods/pir/regressor.py
@@ -17,7 +17,7 @@
     +12/44 FORM_NUMERIC secondary (correct functional form, transcendental
                 constant folded as decimal — reported separately, never summed)
 
-Engine: https://github.com/Qazi-pk/physics-engine (MIT, tag v3.4.1)
+Engine: https://github.com/Qazi-pk/physics-engine (MIT, tag v3.5)
 Paper: https://doi.org/10.5281/zenodo.21351039
 """
 
@@ -28,7 +28,7 @@
 from sklearn.base import BaseEstimator, RegressorMixin
 
 # The classical engine. algorithms/pir/install.sh pip-installs this from the
-# public repo at tag v3.4.1.
+# public repo at tag v3.5.
 from physics_engine.sklearn_adapter import PIRRegressor