diff --git a/.gitignore b/.gitignore
index 3aa70fb..bd8711a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -61,3 +61,5 @@
 /libcxx-12.0.0rc2.src.tar.xz.sig
 /libcxx-12.0.0rc3.src.tar.xz
 /libcxx-12.0.0rc3.src.tar.xz.sig
+/libcxx-12.0.0rc4.src.tar.xz
+/libcxx-12.0.0rc4.src.tar.xz.sig
diff --git a/libcxx.spec b/libcxx.spec
index 69d31c7..db05c8b 100644
--- a/libcxx.spec
+++ b/libcxx.spec
@@ -1,8 +1,8 @@
 # If you need to bootstrap this, turn this on.
 # Otherwise, you have a loop with libcxxabi
 %global bootstrap 0
-%global rc_ver 3
-%global baserelease 5
+%global rc_ver 4
+%global baserelease 6
 
 %global libcxx_srcdir libcxx-%{version}%{?rc_ver:rc%{rc_ver}}.src
 
@@ -138,6 +138,9 @@ install -m 0644 src/include/* %{buildroot}%{_includedir}/libcxx-internal/
 
 
 %changelog
+* Fri Apr 02 2021 sguelton@redhat.com - 12.0.0-0.6.rc4
+- New upstream release candidate
+
 * Thu Mar 11 2021 sguelton@redhat.com - 12.0.0-0.5.rc3
 - LLVM 12.0.0 rc3
 
diff --git a/sources b/sources
index d662da2..60abc7d 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
-SHA512 (libcxx-12.0.0rc3.src.tar.xz) = fcc450c3520b75a88633bb30ff6c865493da30584988413d6bebbce5ecf926656deecafe987c5fa2a8046807d4e119421b83c3c8a2489613eae3970960231843
-SHA512 (libcxx-12.0.0rc3.src.tar.xz.sig) = 1dfd055f55fc74af8780574362ee7e93bb0b050088dd147e9da89496c3eeb087148c5653fb5b78689d530a267525c7b9220edd62c36fb9c1011cf6acd663536b
+SHA512 (libcxx-12.0.0rc4.src.tar.xz) = 7b6343bae357b5369e7f8719ddd07c37b60e3a92503aca93fadb59c82ceaf9832a57b8967f6f5f24454d2c198a98e2d0bb31c81bca06de07870dae710c8fd264
+SHA512 (libcxx-12.0.0rc4.src.tar.xz.sig) = 79fa55edffe6f1c2793d6c59d649c55613fdb399195c21acf03effbae02f728b1326337f3c348188cb7e097eea7c06a5805179047405a62d2d76a9314d560d3d