diff --git a/README.md b/README.md
index 88d4c2c..43da4e4 100644
--- a/README.md
+++ b/README.md
@@ -40,9 +40,7 @@ Note that `Tutorial Notebook 4` will not run correctly in Binder as it requires
 Compatibility
 --------------
 
-The code was developed and tested with Python version 3.8. The minimum required Python version is 3.6. If you install the dependencies of xrdfit using the 
-specification in requirements.txt, this will use the same package versions used by the developers. While this is good for reproducibility, it is worth noting that
-if you are using a newer Python version (> 3.8), some of these packages may not have binary wheels for your version and may require compilation.
+The latest version of xrdfit was tested with Python version 3.10. The minimum required Python version is 3.7.
 
 Required libraries
 --------------------
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 6140b4d..6986de7 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -22,7 +22,7 @@
 author = 'Peter Crowther and Christopher Daniel'
 
 # The full version, including alpha/beta/rc tags
-release = '1.2.1'
+release = '1.3.0'
 
 
 # -- General configuration ---------------------------------------------------
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 10c594e..4825c89 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -7,7 +7,7 @@ xrdfit documentation
 Installation
 ==============
 
-``xrdfit`` is compatible with Python 3.6+.
+``xrdfit`` is compatible with Python 3.7+.
 
 Use :command:`pip` to install the latest stable version of ``xrdfit``:
 
diff --git a/readthedocs.yaml b/readthedocs.yaml
index 98e3e6b..5329526 100644
--- a/readthedocs.yaml
+++ b/readthedocs.yaml
@@ -3,7 +3,7 @@
 version: 2
 
 python:
-  version: 3.6
+  version: 3.7
   install:
     - requirements: requirements.txt
     - method: setuptools
diff --git a/requirements.txt b/requirements.txt
index 28d9516..3b11037 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ matplotlib
 pandas
 dill
 tqdm
-lmfit
+lmfit>=1.1.0
 notebook
 ipywidgets
 PyYAML
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 8fbd8e4..8397231 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
 setup(
     name='xrdfit',
-    version='1.2.1',
+    version='1.3.0',
     description='Automated fitting of XRD peaks using Pseudo-Voight fits',
     author='Peter Crowther, Christopher Daniel',
     long_description=long_description,
@@ -27,5 +27,5 @@
         "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
         "Operating System :: OS Independent",
     ],
-    python_requires='>=3.6',
-)
\ No newline at end of file
+    python_requires='>=3.7',
+)
diff --git a/tutorial notebooks/3 - Fitting peaks over time.ipynb b/tutorial notebooks/3 - Fitting peaks over time.ipynb
index 67ee72b..680fce0 100644
--- a/tutorial notebooks/3 - Fitting peaks over time.ipynb	
+++ b/tutorial notebooks/3 - Fitting peaks over time.ipynb	
@@ -132,7 +132,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "In this case the errors on the parameters are mostly small relative to the magnitude of the parameters they look particularly large in this case because the fit parameters do not change significantly. This is because the 10 example files represent only a short time period where little was changing in the material.\n",
+    "In this case the errors on the parameters are mostly small relative to the magnitude of the parameters. They look particularly large in this case because the fit parameters do not change significantly. This is because the 10 example files represent only a short time period where little was changing in the material.\n",
     "\n",
     "Error bars are plotted by default, to turn them off you can use the `show_error` parameter:"
    ]
diff --git a/xrdfit/pv_fit.py b/xrdfit/pv_fit.py
index 897f79e..805ff65 100644
--- a/xrdfit/pv_fit.py
+++ b/xrdfit/pv_fit.py
@@ -29,7 +29,7 @@ def do_pv_fit(peak_data: np.ndarray, peak_param: "PeakParams") -> lmfit.model.Mo
             model += lmfit.models.PseudoVoigtModel(prefix=prefix)
         else:
             model = lmfit.models.PseudoVoigtModel(prefix=prefix)
-    model += lmfit.Model(lambda background: background)
+    model += lmfit.Model(lambda x, background: background)
 
     two_theta = peak_data[:, 0]
     intensity = peak_data[:, 1]