diff --git a/cad/py-amaranth/Makefile b/cad/py-amaranth/Makefile
index 5c7a2cdd8790..e8f694c65e8d 100644
--- a/cad/py-amaranth/Makefile
+++ b/cad/py-amaranth/Makefile
@@ -1,59 +1,55 @@
 PORTNAME=	amaranth
 DISTVERSIONPREFIX=	v
-DISTVERSION=	0.3-160
-DISTVERSIONSUFFIX=	-gb952005
+DISTVERSION=	0.4.0
 CATEGORIES=	cad python
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Amaranth hardware definition language
 WWW=		https://amaranth-lang.org/docs/amaranth/latest/
 
 LICENSE=	BSD3CLAUSE
 
-BUILD_DEPENDS=	${PY_SETUPTOOLS} \
-		${PYTHON_PKGNAMEPREFIX}setuptools_scm>0:devel/py-setuptools_scm@${PY_FLAVOR} \
+BUILD_DEPENDS=	${PYTHON_PKGNAMEPREFIX}pdm-backend>0:devel/py-pdm-backend@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}wheel>0:devel/py-wheel@${PY_FLAVOR}
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}Jinja2>=3.0:devel/py-Jinja2@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}pyvcd>0:cad/py-pyvcd@${PY_FLAVOR}
+TEST_DEPENDS=	sby:cad/symbiyosys \
+		yosys:cad/yosys
 
 USES=		python
 USE_PYTHON=	pep517 autoplist pytest
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	amaranth-lang
 
 NO_ARCH=	yes
 
-# workaround for https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272771
-PEP517_INSTALL_CMD=	${PYTHON_CMD} -m installer --destdir ${STAGEDIR} --prefix ${PREFIX} ${BUILD_WRKSRC}/dist/${PORTNAME:C|[-_]+|_|g}-${DISTVERSION:S/-/.post/}*.whl
+TEST_ENV=	${MAKE_ENV} PYTHONPATH=${STAGEDIR}${PYTHONPREFIX_SITELIBDIR}
 
 post-patch:
-	@${REINPLACE_CMD} \
-		-e 's|from setuptools_scm.git import parse as parse_git|return "v${DISTVERSION}"|' \
-		${WRKSRC}/setup.py
 	@${REINPLACE_CMD} \
 		-e 's|%%VERSION%%|${DISTVERSION}|' \
 		${WRKSRC}/pyproject.toml
 
 do-install: # workaround for https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272771
 	@${MKDIR} ${STAGEDIR}${PYTHONPREFIX_SITELIBDIR}
 	@cd ${INSTALL_WRKSRC} && ${SETENV} ${MAKE_ENV} ${PEP517_INSTALL_CMD}
 	@${PYTHON_CMD} -B ${PORTSDIR}/Mk/Scripts/strip_RECORD.py \
 		${STAGEDIR}${PYTHONPREFIX_SITELIBDIR}/${PORTNAME:C|[-_]+|_|g}-${DISTVERSION:S/-/.post/}*.dist-info/RECORD >> ${_PYTHONPKGLIST}
 	@${REINPLACE_CMD} \
 		-e '/\.pyc$$/d' \
 		-e 's|^|${PYTHONPREFIX_SITELIBDIR}/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../etc/|etc/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../bin/|bin/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../include/|include/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../lib/|lib/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../libdata/|libdata/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../libexec/|libexec/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../man/|man/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../sbin/|sbin/|' \
 		-e 's|^${PYTHONPREFIX_SITELIBDIR}/../../../share/|share/|' \
 			${_PYTHONPKGLIST}
 	@cd ${STAGEDIR}${PREFIX} && ${FIND} lib -name '*.pyc' >> ${_PYTHONPKGLIST}
 
 .include <bsd.port.mk>
diff --git a/cad/py-amaranth/distinfo b/cad/py-amaranth/distinfo
index 4bb3f520c209..8642e68838bb 100644
--- a/cad/py-amaranth/distinfo
+++ b/cad/py-amaranth/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1690525544
-SHA256 (amaranth-lang-amaranth-v0.3-160-gb952005_GH0.tar.gz) = 8bdab7fbd10dc07d99a383316b2503dd00733b6dd99e787e0ffe4cb27f8eb112
-SIZE (amaranth-lang-amaranth-v0.3-160-gb952005_GH0.tar.gz) = 261933
+TIMESTAMP = 1704939098
+SHA256 (amaranth-lang-amaranth-v0.4.0_GH0.tar.gz) = f377c113af9d6772331509fff72cf19d060cd16849981ce32b6eeb94d64c62eb
+SIZE (amaranth-lang-amaranth-v0.4.0_GH0.tar.gz) = 307888
diff --git a/cad/py-amaranth/files/patch-pyproject.toml b/cad/py-amaranth/files/patch-pyproject.toml
index 00ed445714f6..e19d759d8171 100644
--- a/cad/py-amaranth/files/patch-pyproject.toml
+++ b/cad/py-amaranth/files/patch-pyproject.toml
@@ -1,37 +1,17 @@
---- pyproject.toml.orig	2023-07-27 13:04:20 UTC
+--- pyproject.toml.orig	2023-12-13 09:29:50 UTC
 +++ pyproject.toml
-@@ -1,12 +1,13 @@
- # Project metadata
+@@ -4,12 +4,13 @@ source = "scm"
+ source = "scm"
  
  [project]
--dynamic = ["version", "urls"]
-+dynamic = ["urls"]
+-dynamic = ["version"]
++dynamic = []
  
  name = "amaranth"
  description = "Amaranth hardware definition language"
  authors = [{name = "Amaranth HDL contributors"}]
  license = {file = "LICENSE.txt"}
 +version = "%%VERSION%%"
  
  requires-python = "~=3.8"
  dependencies = [
-@@ -26,7 +27,7 @@ amaranth-rpc = "amaranth.rpc:main"
- # Build system configuration
- 
- [build-system]
--requires = ["wheel", "setuptools>=67.0", "setuptools_scm[toml]>=6.2"]
-+requires = ["wheel", "setuptools>0", "setuptools_scm[toml]>=6.2"]
- build-backend = "setuptools.build_meta"
- 
- [tool.setuptools]
-@@ -36,8 +37,8 @@ build-backend = "setuptools.build_meta"
- # Add a workaround to improve experience for people upgrading from old checkouts.
- packages = ["amaranth"]
- 
--[tool.setuptools_scm]
--local_scheme = "node-and-timestamp"
-+#[tool.setuptools_scm]
-+#local_scheme = "node-and-timestamp"
- 
- # Development workflow configuration
-