diff --git a/Makefile.uk b/Makefile.uk
index 9939c6c..e44aaf6 100644
--- a/Makefile.uk
+++ b/Makefile.uk
@@ -50,7 +50,7 @@ endif
 ################################################################################
 # Sources
 ################################################################################
-LIBCXX_VERSION=14.0.6
+LIBCXX_VERSION=15.0.0
 LIBCXX_URL=https://github.com/llvm/llvm-project/releases/download/llvmorg-$(LIBCXX_VERSION)/libcxx-$(LIBCXX_VERSION).src.tar.xz
 LIBCXX_PATCHDIR=$(LIBCXX_BASE)/patches
 $(eval $(call fetch,libcxx,$(LIBCXX_URL)))
@@ -102,7 +102,7 @@ LIBCXX_SUPPRESS_FLAGS-$(call have_gcc) += -Wno-maybe-uninitialized
 LIBCXX_SUPPRESS_FLAGS-$(call have_gcc) += -Wno-unknown-pragmas
 
 LIBCXX_CFLAGS-y    += $(LIBCXX_CONFIG_FLAGS)
-LIBCXX_CXXFLAGS-y  += $(LIBCXX_CONFIG_FLAGS) -std=c++2a
+LIBCXX_CXXFLAGS-y  += $(LIBCXX_CONFIG_FLAGS) -std=c++2a -fpermissive
 LIBCXX_CXXFLAGS-$(call have_gcc) += -Wno-literal-suffix
 LIBCXX_CXXFLAGS-$(call have_gcc) += -Wno-dangling-reference
 
diff --git a/patches/0001-Remove-ABI-tag.patch b/patches/0001-Remove-ABI-tag.patch
new file mode 100644
index 0000000..8abad25
--- /dev/null
+++ b/patches/0001-Remove-ABI-tag.patch
@@ -0,0 +1,50 @@
+From 316e4eee534e9474e34f928d5451032556377853 Mon Sep 17 00:00:00 2001
+From: Mamta Shukla <mamtashukla555@gmail.com>
+Date: Sun, 6 Aug 2023 22:49:45 +0200
+Subject: [PATCH] Remove ABI tag
+
+Signed-off-by: Mamta Shukla <mamtashukla555@gmail.com>
+---
+ include/__support/musl/xlocale.h | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/include/__support/musl/xlocale.h b/include/__support/musl/xlocale.h
+index f564c87..97b4876 100644
+--- a/include/__support/musl/xlocale.h
++++ b/include/__support/musl/xlocale.h
+@@ -24,27 +24,27 @@
+ extern "C" {
+ #endif
+ 
+-inline _LIBCPP_HIDE_FROM_ABI long long
++inline long long
+ strtoll_l(const char *__nptr, char **__endptr, int __base, locale_t) {
+   return ::strtoll(__nptr, __endptr, __base);
+ }
+ 
+-inline _LIBCPP_HIDE_FROM_ABI unsigned long long
++inline unsigned long long
+ strtoull_l(const char *__nptr, char **__endptr, int __base, locale_t) {
+   return ::strtoull(__nptr, __endptr, __base);
+ }
+ 
+-inline _LIBCPP_HIDE_FROM_ABI long long
++inline long long
+ wcstoll_l(const wchar_t *__nptr, wchar_t **__endptr, int __base, locale_t) {
+   return ::wcstoll(__nptr, __endptr, __base);
+ }
+ 
+-inline _LIBCPP_HIDE_FROM_ABI long long
++inline long long
+ wcstoull_l(const wchar_t *__nptr, wchar_t **__endptr, int __base, locale_t) {
+   return ::wcstoull(__nptr, __endptr, __base);
+ }
+ 
+-inline _LIBCPP_HIDE_FROM_ABI long double
++inline long double
+ wcstold_l(const wchar_t *__nptr, wchar_t **__endptr, locale_t) {
+   return ::wcstold(__nptr, __endptr);
+ }
+-- 
+2.25.1
+
diff --git a/patches/0001-Use-__is_convertible-built-in-when-available.patch b/patches/0001-Use-__is_convertible-built-in-when-available.patch
deleted file mode 100644
index faf471c..0000000
--- a/patches/0001-Use-__is_convertible-built-in-when-available.patch
+++ /dev/null
@@ -1,24 +0,0 @@
-diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
-index 3391999675..ab126d000d 100644
---- a/include/type_traits
-+++ b/include/type_traits
-@@ -1659,11 +1659,18 @@ struct __is_core_convertible<_Tp, _Up, decltype(
- 
- // is_convertible
- 
--#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
-+#if __has_builtin(__is_convertible) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
-+
-+template <class _T1, class _T2>
-+struct _LIBCPP_TEMPLATE_VIS is_convertible : public integral_constant<bool, __is_convertible(_T1, _T2)> {};
-+
-+#elif __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
- 
- template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
-     : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
- 
-+// TODO: Remove this fallback when GCC < 13 support is no longer required.
-+// GCC 13 has the __is_convertible built-in.
- #else  // __has_feature(is_convertible_to)
- 
- namespace __is_convertible_imp