diff --git a/CHANGELOG.md b/CHANGELOG.md
index d8e28d9..c750d59 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.4.x
+### 0.4.0
+- Fixed critical issue preventing the program from functioning.
+- Updated compatibility to align with **upcoming** optima35 **release** (RC).
+
 ## 0.3.x
 ### 0.3.6: Patch
 - Added check if any exif options are empty.
diff --git a/pyproject.toml b/pyproject.toml
index d3b5772..efc05de 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ authors = [{ name = "Mr. Finchum" }]
 description = "User interface for optima35."
 readme = "pip_README.md"
 requires-python = ">=3.8"
-dependencies = ["optima35>=0.6.7", "pyside6", "PyYAML", "packaging"]
+dependencies = ["optima35>=1.0.0", "pyside6", "PyYAML", "packaging"]
 classifiers = [
     "Programming Language :: Python :: 3",
     "License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)",
diff --git a/src/OptimaLab35/gui.py b/src/OptimaLab35/gui.py
index 5aac4c1..4fc4afb 100644
--- a/src/OptimaLab35/gui.py
+++ b/src/OptimaLab35/gui.py
@@ -296,7 +296,6 @@ class OptimaLab35(QMainWindow, Ui_MainWindow):
     def start_process(self):
         self.toggle_buttons(False)
         u = self.update_settings()
-        print(f"u in startinset_xif: {u}")
         if u != None:  # Get all user selected data
             QMessageBox.warning(self, "Warning", f"Error: {u}")
             self.toggle_buttons(True)
@@ -321,7 +320,7 @@ class OptimaLab35(QMainWindow, Ui_MainWindow):
 
             input_path = os.path.join(input_folder, image_file)
 
-            self.o.insert_dict_to_image(
+            self.o.insert_exif_to_image(
                 exif_dict = self.settings["user_selected_exif"],
                 image_path = input_path,
                 gps = self.settings["gps"])
@@ -334,7 +333,6 @@ class OptimaLab35(QMainWindow, Ui_MainWindow):
     def startinsert_exif(self):
         self.toggle_buttons(False)
         u = self.update_settings()
-        print(f"u in startinset_xif: {u}")
         if u != None:  # Get all user selected data
             QMessageBox.warning(self, "Warning", f"Error: {u}")
             self.toggle_buttons(True)
@@ -435,9 +433,10 @@ class OptimaLab35(QMainWindow, Ui_MainWindow):
             self.settings["user_selected_exif"] = None
             self.settings["gps"] = None
 
-        u = self.check_selected_exif(self.settings["user_selected_exif"])
-        if u != True:
-            return u
+        if self.settings["user_selected_exif"] is not None:
+            u = self.check_selected_exif(self.settings["user_selected_exif"])
+            if u != True:
+                return u
 
     # Helper functions, low level
     def handle_exif_file(self, do):
@@ -476,10 +475,10 @@ class PreviewWindow(QMainWindow, Ui_Preview_Window):
         if not os.path.isfile(path):
             return
         try:
-            img = self.o.process_image(
-                save = False,
+            img = self.o.process_image_object(
                 image_input_file = path,
-                image_output_file = "",
+                resize = 50,
+                watermark = "PREVIEW",
                 grayscale = self.ui.grayscale_checkBox.isChecked(),
                 brightness = int(self.ui.brightness_spinBox.text()),
                 contrast = int(self.ui.contrast_spinBox.text())
@@ -526,7 +525,7 @@ class ImageProcessorRunnable(QRunnable):
                 image_name = os.path.splitext(image_file)[0]
             output_path = os.path.join(output_folder, image_name)
 
-            self.o.process_image(
+            self.o.process_and_save_image(
                 image_input_file = input_path,
                 image_output_file = output_path,
                 file_type = self.settings["file_format"],