diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 161171e68..aa6058c1b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,6 +22,7 @@ jobs:
         - 2.7
         - 3.5
         - 3.8
+        - 3.9
         - pypy2
         - pypy3
 
@@ -32,34 +33,33 @@ jobs:
         # We support three optional keys: args (both build), args1 (first
         # build), and args2 (second build).
         include:
+          # Just add a key
           - runs-on: ubuntu-latest
             python: 3.6
             arch: x64
             args: >
               -DPYBIND11_FINDPYTHON=ON
+          - runs-on: windows-latest
+            python: 3.6
+            arch: x64
+            args: >
+              -DPYBIND11_FINDPYTHON=ON
+          - runs-on: ubuntu-latest
+            python: 3.8
+            arch: x64
+            args: >
+              -DPYBIND11_FINDPYTHON=ON
+
+          # New runs
           - runs-on: windows-2016
             python: 3.7
             arch: x86
             args2: >
               -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
-          - runs-on: windows-latest
-            python: 3.6
-            arch: x64
-            args: >
-              -DPYBIND11_FINDPYTHON=ON
           - runs-on: windows-latest
             python: 3.7
             arch: x64
 
-          - runs-on: ubuntu-latest
-            python: 3.9-dev
-            arch: x64
-          - runs-on: macos-latest
-            python: 3.9-dev
-            arch: x64
-            args: >
-              -DPYBIND11_FINDPYTHON=ON
-
         # These items will be removed from the build matrix, keys must match.
         exclude:
             # Currently 32bit only, and we build 64bit
@@ -75,12 +75,11 @@ jobs:
             python: 3.8
             arch: x64
           - runs-on: windows-latest
-            python: 3.9-dev
+            python: 3.9
             arch: x64
 
     name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • ${{ matrix.arch }} ${{ matrix.args }}"
     runs-on: ${{ matrix.runs-on }}
-    continue-on-error: ${{ endsWith(matrix.python, 'dev') }}
 
     steps:
     - uses: actions/checkout@v2
@@ -196,7 +195,7 @@ jobs:
           - 3.9
           - 5
           - 7
-          - 9
+          - 10
           - dev
 
     name: "🐍 3 • Clang ${{ matrix.clang }} • x64"
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 3a4fb6dc4..87a769e19 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -126,6 +126,11 @@ Smaller or developer focused features:
 * Throw if conversion to ``str`` fails.
   `#2477 <https://github.com/pybind/pybind11/pull/2477>`_
 
+* Throw error if conversion to a pybind11 type if the Python object isn't a
+  valid instance of that type, such as ``py::bytes(o)`` when ``py::object o``
+  isn't a bytes instance.
+  `#2349 <https://github.com/pybind/pybind11/pull/2349>`_
+
 * Pointer to ``std::tuple`` & ``std::pair`` supported in cast.
   `#2334 <https://github.com/pybind/pybind11/pull/2334>`_
 
diff --git a/docs/upgrade.rst b/docs/upgrade.rst
index 02d9049bb..12a7a2203 100644
--- a/docs/upgrade.rst
+++ b/docs/upgrade.rst
@@ -23,6 +23,10 @@ An error is now thrown when ``__init__`` is forgotten on subclasses. This was
 incorrect before, but was not checked. Add a call to ``__init__`` if it is
 missing.
 
+A ``py::type_error`` is now thrown when casting to a subclass (like
+``py::bytes`` from ``py::object``) if the conversion is not valid. Make a valid
+conversion instead.
+
 The undocumented ``h.get_type()`` method has been deprecated and replaced by
 ``py::type::of(h)``.
 
diff --git a/include/pybind11/pytypes.h b/include/pybind11/pytypes.h
index 103badcc2..30d7f9aef 100644
--- a/include/pybind11/pytypes.h
+++ b/include/pybind11/pytypes.h
@@ -813,9 +813,9 @@ PYBIND11_NAMESPACE_END(detail)
     { if (!m_ptr) throw error_already_set(); }
 
 #define PYBIND11_OBJECT_CHECK_FAILED(Name, o) \
-    type_error("Object of type '" + \
-               pybind11::detail::get_fully_qualified_tp_name(Py_TYPE(o.ptr())) + \
-               "' is not an instance of '" #Name "'")
+    ::pybind11::type_error("Object of type '" + \
+                           ::pybind11::detail::get_fully_qualified_tp_name(Py_TYPE(o.ptr())) + \
+                           "' is not an instance of '" #Name "'")
 
 #define PYBIND11_OBJECT(Name, Parent, CheckFun) \
     PYBIND11_OBJECT_COMMON(Name, Parent, CheckFun) \