diff --git a/Mk/bsd.port.mk b/Mk/bsd.port.mk
--- a/Mk/bsd.port.mk
+++ b/Mk/bsd.port.mk
@@ -1164,7 +1164,7 @@
 .    endif
 _EXPORTED_VARS+=	OSVERSION
 
-.    if ${OPSYS} == FreeBSD && (${OSVERSION} < 1304000 || (${OSVERSION} >= 1400000 && ${OSVERSION} < 1401000))
+.    if ${OPSYS} == FreeBSD && (${OSVERSION} < 1304000 || (${OSVERSION} >= 1400000 && ${OSVERSION} < 1402000))
 _UNSUPPORTED_SYSTEM_MESSAGE=	Ports Collection support for your ${OPSYS} version has ended, and no ports\
 								are guaranteed to build on this system. Please upgrade to a supported release.
 .      if defined(ALLOW_UNSUPPORTED_SYSTEM)
diff --git a/devel/boost-libs/Makefile b/devel/boost-libs/Makefile
--- a/devel/boost-libs/Makefile
+++ b/devel/boost-libs/Makefile
@@ -17,7 +17,6 @@
 # following conditions are satisfied.
 # * OSVERSION is included in either of following ranges.
 #   1. 1500000 <= OSVERSION < 1500017
-#   2. 1400000 <= OSVERSION < 1400509 (no longer relevant)
 # * Base system is built with WITH_LLVM_ASSERTIONS variable set.
 # So if your base system fulfills them you need to use LLVM ports to
 # build this port.
diff --git a/devel/libdispatch/Makefile b/devel/libdispatch/Makefile
--- a/devel/libdispatch/Makefile
+++ b/devel/libdispatch/Makefile
@@ -19,15 +19,6 @@
 
 .include <bsd.port.options.mk>
 
-#.if ${OPSYS} == FreeBSD && ${OSVERSION} >= 1400000 && ${OSVERSION} < 1400079
-#USES+=	llvm:max=17,build
-#USES:=	${USES:Ncompiler\:*} # XXX avoid warnings
-#CC=	${_LLVM_MK_PREFIX}/bin/clang
-#CPP=	${_LLVM_MK_PREFIX}/bin/clang-cpp
-#CXX=	${_LLVM_MK_PREFIX}/bin/clang++
-#LD?=	${_LLVM_MK_PREFIX}/bin/ld
-#.endif
-
 .if ${OPSYS} == FreeBSD && (${ARCH} == armv7 || ${ARCH} == i386 || ${ARCH} == powerpc)
 CFLAGS+=	-Wno-incompatible-function-pointer-types
 .endif
diff --git a/editors/imhex/Makefile b/editors/imhex/Makefile
--- a/editors/imhex/Makefile
+++ b/editors/imhex/Makefile
@@ -112,9 +112,7 @@
 .endif
 
 # After LLVM 18 import into the base system
-.if ((${OSREL:R} == 15 && ${OSVERSION} >= 1500018) \
-    || (${OSREL:R} == 14 && ${OSVERSION} >= 1400511) \
-    || (${OSREL:R} == 13 && ${OSVERSION} >= 1303503))
+.if (${OSREL:R} == 15 && ${OSVERSION} >= 1500018)
 CXXFLAGS+=	-fexperimental-library -D_LIBCPP_ENABLE_EXPERIMENTAL
 .endif
 
diff --git a/editors/libreoffice/Makefile b/editors/libreoffice/Makefile
--- a/editors/libreoffice/Makefile
+++ b/editors/libreoffice/Makefile
@@ -367,11 +367,6 @@
 
 .include <bsd.port.pre.mk>
 
-.if ${OPSYS} == FreeBSD && ( \
-    (${OSVERSION} >= 1400051 && ${OSVERSION} < 1400057))
-BROKEN=	please update FreeBSD base system first to fix an ABI incompatibility
-.endif
-
 .if ${ARCH} == powerpc || ${ARCH} == powerpcspe || ${ARCH} == powerpc64
 CONFIGURE_ARGS+=	--disable-skia
 .endif
diff --git a/graphics/dspdfviewer/Makefile b/graphics/dspdfviewer/Makefile
--- a/graphics/dspdfviewer/Makefile
+++ b/graphics/dspdfviewer/Makefile
@@ -43,31 +43,18 @@
 .if ${OPSYS} == FreeBSD && ${CHOSEN_COMPILER_TYPE} == clang
 # (rene) also related to issue #191 which is still open as of 2020-10-21
 CFLAGS+=	-Wno-error=zero-as-null-pointer-constant
-.endif
-
 # Fixes build failure for Clang 8.0.0
-.if ${OPSYS} == FreeBSD && ${CHOSEN_COMPILER_TYPE} == clang
 CFLAGS+=	-Wno-error=extra-semi-stmt
-.endif
-
 # Fixes build failure for Clang 11.0.0
-.if ${OPSYS} == FreeBSD && ${CHOSEN_COMPILER_TYPE} == clang
 CFLAGS+=	-Wno-error=suggest-destructor-override
 CFLAGS+=	-Wno-error=suggest-override
-.endif
-
 # Fixes build failure for Clang 14.0.3
-.if ${OPSYS} == FreeBSD && ${OSVERSION} >= 1400059 && ${CHOSEN_COMPILER_TYPE} == clang
+.if ${OSVERSION} >= 1400059
 CFLAGS+=       -Wno-error=bitwise-instead-of-logical
 .endif
-
 # Fixes build failure for Clang 16.0.6
-.if ${OPSYS} == FreeBSD && ${CHOSEN_COMPILER_TYPE} == clang
 CFLAGS+=       -Wno-error=unsafe-buffer-usage
-.endif
-
 # Fixes build failure for Clang 18.1.4
-.if ${OPSYS} == FreeBSD && (${OSVERSION} >= 1304000 || ${OSVERSION} >= 1401000 || ${OSVERSION} >= 1500018) && ${CHOSEN_COMPILER_TYPE} == clang
 CFLAGS+=       -Wno-error=switch-default
 .endif