Drop support for marshmallow v3

.github/workflows/build-release.yml

@@ -14,11 +14,10 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { name: "3.10", tox: py310-marshmallow3 }
-          - { name: "3.14", tox: py314-marshmallow3 }
+          - { name: "3.10", tox: py310 }
+          - { name: "3.14", tox: py314 }
           - { name: "lowest", tox: py310-lowest }
           - { name: "dev", tox: py314-marshmallowdev }
-          - { name: "mypy-ma3", tox: mypy-marshmallow3 }
           - { name: "mypy-madev", tox: mypy-marshmallowdev }
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6

CHANGELOG.rst

@@ -1,6 +1,13 @@
 Changelog
 ---------
 
+unreleased
+++++++++++
+
+Other changes:
+
+* Drop support for marshmallow 3, which is EOL.
+
 1.5.0 (2026-04-01)
 ++++++++++++++++++
 

pyproject.toml

@@ -3,11 +3,10 @@ name = "marshmallow-sqlalchemy"
 version = "1.5.0"
 description = "SQLAlchemy integration with the marshmallow (de)serialization library"
 readme = "README.rst"
-license = { file = "LICENSE" }
-maintainers = [{ name = "Steven Loria", email = "sloria1@gmail.com" }]
+license = "MIT"
+maintainers = [{ name = "Steven Loria", email = "oss@stevenloria.com" }]
 classifiers = [
   "Intended Audience :: Developers",
-  "License :: OSI Approved :: MIT License",
   "Programming Language :: Python :: 3",
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
@@ -16,10 +15,7 @@ classifiers = [
   "Programming Language :: Python :: 3.14",
 ]
 requires-python = ">=3.10"
-dependencies = [
-  "marshmallow>=3.18.0",
-  "SQLAlchemy>=1.4.40,<3.0",
-]
+dependencies = ["marshmallow>=4.0.0", "SQLAlchemy>=1.4.40,<3.0"]
 
 [project.urls]
 Changelog = "https://marshmallow-sqlalchemy.readthedocs.io/en/latest/changelog.html"
@@ -37,12 +33,7 @@ docs = [
   "sphinxext-opengraph",
 ]
 tests = ["pytest", "pytest-lazy-fixtures"]
-dev = [
-  { include-group = "tests" },
-  "tox",
-  "tox-uv",
-  "pre-commit>=3.5,<5.0",
-]
+dev = [{ include-group = "tests" }, "tox", "tox-uv", "pre-commit>=3.5,<5.0"]
 
 [tool.uv]
 default-groups = ["dev"]

tox.ini

@@ -1,25 +1,23 @@
 [tox]
 envlist=
     lint
-    py{310,311,312,313,314}-marshmallow3
+    py{310,311,312,313,314}
     py314-marshmallowdev
     py310-lowest
-    mypy-marshmallow{3,dev}
+    mypy-marshmallowdev
     docs
 
 [testenv]
 dependency_groups = tests
 deps =
-    marshmallow3: marshmallow>=3.18.0,<4.0.0
     marshmallowdev: https://github.com/marshmallow-code/marshmallow/archive/dev.tar.gz
-    lowest: marshmallow==3.18.0
+    lowest: marshmallow==4.0.0
     lowest: sqlalchemy==1.4.40
 commands = pytest {posargs}
 
-[testenv:mypy-marshmallow{3,dev}]
+[testenv:mypy-marshmallowdev]
 deps =
     mypy>=1.14.1
-    marshmallow3: marshmallow>=3.18.0,<4.0.0
     marshmallowdev: https://github.com/marshmallow-code/marshmallow/archive/dev.tar.gz
 commands = mypy