diff --git a/pysr/julia_import.py b/pysr/julia_import.py
index 4ea6b88d..26288c75 100644
--- a/pysr/julia_import.py
+++ b/pysr/julia_import.py
@@ -64,5 +64,8 @@ def _import_juliacall():
 jl.seval("using SymbolicRegression")
 SymbolicRegression = jl.SymbolicRegression
 
+# Expose `D` operator:
+jl.seval("using SymbolicRegression: D")
+
 jl.seval("using Pkg: Pkg")
 Pkg = jl.Pkg
diff --git a/pysr/juliapkg.json b/pysr/juliapkg.json
index 9c28c96e..1673a713 100644
--- a/pysr/juliapkg.json
+++ b/pysr/juliapkg.json
@@ -3,7 +3,7 @@
     "packages": {
         "SymbolicRegression": {
             "uuid": "8254be44-1295-4e6a-a16d-46603ac705cb",
-            "version": "=1.2.0"
+            "version": "=1.4.0"
         },
         "Serialization": {
             "uuid": "9e88b42a-f829-5b0c-bbe9-9e923198166b",
diff --git a/pysr/param_groupings.yml b/pysr/param_groupings.yml
index f43c67f9..769e6647 100644
--- a/pysr/param_groupings.yml
+++ b/pysr/param_groupings.yml
@@ -92,6 +92,7 @@
   - print_precision
   - progress
   - logger_spec
+  - input_stream
 - Environment:
   - temp_equation_file
   - tempdir
diff --git a/pysr/sr.py b/pysr/sr.py
index c23805b4..c7beae23 100644
--- a/pysr/sr.py
+++ b/pysr/sr.py
@@ -618,6 +618,12 @@ class PySRRegressor(MultiOutputMixin, RegressorMixin, BaseEstimator):
         Logger specification for the Julia backend. See, for example,
         `TensorBoardLoggerSpec`.
         Default is `None`.
+    input_stream : str
+        The stream to read user input from. By default, this is `"stdin"`.
+        If you encounter issues with reading from `stdin`, like a hang,
+        you can simply pass `"devnull"` to this argument. You can also
+        reference an arbitrary Julia object in the `Main` namespace.
+        Default is `"stdin"`.
     run_id : str
         A unique identifier for the run. Will be generated using the
         current date and time if not provided.
@@ -863,6 +869,7 @@ def __init__(
         print_precision: int = 5,
         progress: bool = True,
         logger_spec: AbstractLoggerSpec | None = None,
+        input_stream: str = "stdin",
         run_id: str | None = None,
         output_directory: str | None = None,
         temp_equation_file: bool = False,
@@ -969,6 +976,7 @@ def __init__(
         self.print_precision = print_precision
         self.progress = progress
         self.logger_spec = logger_spec
+        self.input_stream = input_stream
         # - Project management
         self.run_id = run_id
         self.output_directory = output_directory
@@ -1888,6 +1896,8 @@ def _run(
             else "nothing"
         )
 
+        input_stream = jl.seval(self.input_stream)
+
         load_required_packages(
             turbo=self.turbo,
             bumper=self.bumper,
@@ -2002,6 +2012,7 @@ def _run(
             crossover_probability=self.crossover_probability,
             skip_mutation_failures=self.skip_mutation_failures,
             max_evals=self.max_evals,
+            input_stream=input_stream,
             early_stop_condition=early_stop_condition,
             seed=seed,
             deterministic=self.deterministic,