diff --git a/.github/workflows/python-push.yml b/.github/workflows/python-push.yml
index f77ce4662..7b67962df 100644
--- a/.github/workflows/python-push.yml
+++ b/.github/workflows/python-push.yml
@@ -103,6 +103,11 @@ jobs:
       if: steps.core-version.outputs.core == 'true'
       run: |
         make docs-validate
+    - name: Recreate hatch test environment
+      shell: bash
+      run: |
+        hatch env remove hatch-test.py${{ matrix.python-version }} 2>/dev/null || true
+        hatch env create hatch-test.py${{ matrix.python-version }}
     - name: Pytest Fast
       if: steps.core-version.outputs.core != 'true'
       run: |
@@ -151,6 +156,11 @@ jobs:
     - name: gen OSCAL models
       run: |
         make gen-oscal
+    - name: Recreate hatch test environment
+      shell: bash
+      run: |
+        hatch env remove hatch-test.py${{ matrix.python-version }} 2>/dev/null || true
+        hatch env create hatch-test.py${{ matrix.python-version }}
     - name: Run tests
       run: |
         make test
diff --git a/README.md b/README.md
index 4248867bc..be556a0a3 100644
--- a/README.md
+++ b/README.md
@@ -93,14 +93,17 @@ A collection of demos utilizing trestle can be found in the related project [com
 ### v4: stable (actively developed)
 
 - supports NIST OSCAL 1.2.1 as well as previous versions
+- supports newly released Mapping Model
 
 ### v3: stable (maintenance mode)
 
 - supports NIST OSCAL 1.1.3 as well as previous versions
+- limited support until June 30, 2026
 
 ### v2: stable (deprecated)
 
 - supports NIST OSCAL 1.0.4 as well as previous versions
+- no longer supported
 
 ## Community meetings and communications
 
diff --git a/docs/index.md b/docs/index.md
index 50ef07db1..1601d8fce 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -37,10 +37,11 @@ Trestle provides tooling to help orchestrate the compliance process across a num
 
 ## Important Note:
 
-The current version of trestle 3.x supports NIST OSCAL 1.1.2.
+The current version of trestle 4.x supports NIST OSCAL 1.2.1.
 Below shows trestle versions correspondence with OSCAL versions:
 
 ```
+trestle 4.x => OSCAL 1.2.1
 trestle 3.x => OSCAL 1.1.2
 trestle 2.x => OSCAL 1.0.4
 trestle 1.x => OSCAL 1.0.2
@@ -51,46 +52,28 @@ Visit [pypi](https://pypi.org/project/compliance-trestle/#history) for trestle r
 
 ## Notes for install of current and older versions of trestle
 
-#### Install of trestle 3.x
+#### Install of trestle 4.x
 
 Use python 3.11.
 
 ```
 python3.11 -m venv venv.trestle
 source venv.trestle/bin/activate
-pip install compliance-trestle==3.6.0
-trestle version
-Trestle version v3.6.0 based on OSCAL version 1.1.2
-```
-
-#### Install of trestle 2.x
-
-Use python 3.10 or higher.
-
-```
-python3.10 -m venv venv.trestle
-source venv.trestle/bin/activate
-pip install compliance-trestle==2.6.0
+pip install compliance-trestle
 trestle version
-Trestle version v2.6.0 based on OSCAL version 1.0.4
+Trestle version v4.0.0 based on OSCAL version 1.2.1
 ```
 
-#### Install of trestle 1.x
-
-Use python 3.9.
+#### Install of trestle 3.x
 
-Due to dependency updates since the release of trestle 1.2.0, perform the following in your venv:
+Use python 3.11.
 
 ```
-python3.9 -m venv venv.trestle
+python3.11 -m venv venv.trestle
 source venv.trestle/bin/activate
-pip install compliance-trestle==1.2.0
-pip uninstall pydantic
-pip uninstall pydantic_core
-pip install pydantic==1.10.2
-pip install requests
+pip install compliance-trestle==3.6.0
 trestle version
-Trestle version v1.2.0 based on OSCAL version 1.0.2
+Trestle version v3.6.0 based on OSCAL version 1.1.2
 ```
 
 ## Why Trestle
diff --git a/docs/reference/API/trestle/oscal/mapping.md b/docs/reference/API/trestle/oscal/mapping.md
new file mode 100644
index 000000000..e6bbdd185
--- /dev/null
+++ b/docs/reference/API/trestle/oscal/mapping.md
@@ -0,0 +1,7 @@
+---
+title: trestle.oscal.mapping
+description: Documentation for trestle.oscal.mapping module
+---
+
+::: trestle.oscal.mapping
+handler: python
diff --git a/docs/reference/API/trestle/tasks/csv_to_oscal_mc.md b/docs/reference/API/trestle/tasks/csv_to_oscal_mc.md
new file mode 100644
index 000000000..78430e001
--- /dev/null
+++ b/docs/reference/API/trestle/tasks/csv_to_oscal_mc.md
@@ -0,0 +1,7 @@
+---
+title: trestle.tasks.csv_to_oscal_mc
+description: Documentation for trestle.tasks.csv_to_oscal_mc module
+---
+
+::: trestle.tasks.csv_to_oscal_mc
+handler: python
diff --git a/docs/reference/API/trestle/tasks/csv_to_oscal_mc_utilities.md b/docs/reference/API/trestle/tasks/csv_to_oscal_mc_utilities.md
new file mode 100644
index 000000000..de2606851
--- /dev/null
+++ b/docs/reference/API/trestle/tasks/csv_to_oscal_mc_utilities.md
@@ -0,0 +1,7 @@
+---
+title: trestle.tasks.csv_to_oscal_mc_utilities
+description: Documentation for trestle.tasks.csv_to_oscal_mc_utilities module
+---
+
+::: trestle.tasks.csv_to_oscal_mc_utilities
+handler: python
diff --git a/pyproject.toml b/pyproject.toml
index 232e62e1e..9066c4ab7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,8 +29,7 @@ classifiers = [
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
-    "Programming Language :: Python :: 3.12",
-    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.12"
 ]
 dependencies = [
     "attrs",
@@ -128,7 +127,7 @@ dependencies = [
 ]
 
 [[tool.hatch.envs.hatch-test.matrix]]
-python = ["3.10", "3.11", "3.12", "3.13"]
+python = ["3.10", "3.11", "3.12"]
 
 [tool.hatch.envs.docs]
 features = ["docs"]