diff --git a/src/acom_music_box/main.py b/src/acom_music_box/main.py
index 83c101ed..db9b6a35 100644
--- a/src/acom_music_box/main.py
+++ b/src/acom_music_box/main.py
@@ -1,6 +1,6 @@
 import os
 import argparse
-from acom_music_box import MusicBox, Examples
+from acom_music_box import MusicBox, Examples, __version__ 
 import datetime
 import sys
 import logging
@@ -40,6 +40,11 @@ def parse_arguments():
         default=0,
         help='Increase logging verbosity. Use -v for info, -vv for debug.'
     )
+    parser.add_argument(
+        '--version',
+        action='version',
+        version=f'MusicBox {__version__}',
+    )
     parser.add_argument(
         '--color-output',
         action='store_true',
diff --git a/src/acom_music_box/music_box.py b/src/acom_music_box/music_box.py
index e9d9aab3..65fe7363 100644
--- a/src/acom_music_box/music_box.py
+++ b/src/acom_music_box/music_box.py
@@ -427,7 +427,7 @@ def create_solver(
         # Create a solver object using the configuration file
         self.solver = musica.create_solver(
             path_to_config,
-            musica.micmsolver.rosenbrock,
+            solver_type,
             number_of_grid_cells)
 
     def solve(self, output_path=None):
@@ -697,16 +697,6 @@ def speciesOrdering(self):
         """
         return musica.species_ordering(self.solver)
 
-    def userDefinedReactionRates(self):
-        """
-        Retrieves the user-defined reaction rates from the solver.
-
-        This function calls the `user_defined_reaction_rates` function from the `musica` module,
-        passing the solver instance from the current object.
-
-        Returns:
-            dict: The dictionary of user-defined reaction rates used in the solver.
-        """
     @classmethod
     def order_reaction_rates(self, curr_conditions, rate_constant_ordering):
         """