diff --git a/configs/15.0/base.mk b/configs/15.0/base.mk
index 39f413c23..4ac45ee00 100644
--- a/configs/15.0/base.mk
+++ b/configs/15.0/base.mk
@@ -49,7 +49,7 @@
 AT_NAME := at
 AT_MAJOR_VERSION := 15.0
 AT_REVISION_NUMBER := 6
-AT_INTERNAL := rc2
+AT_INTERNAL := none
 AT_PREVIOUS_VERSION := 14.0
 
 # Minimum kernel version distributed on supported distros by this AT version,
diff --git a/configs/15.0/release_notes/relfixes.html b/configs/15.0/release_notes/relfixes.html
index e49eda031..c5a8d6c7b 100644
--- a/configs/15.0/release_notes/relfixes.html
+++ b/configs/15.0/release_notes/relfixes.html
@@ -1,5 +1,6 @@
 <li>Power10 enablement.</li>
 <li>Power9 enablement.</li>
+<li>Power10-optimized instruction scheduling in GCC.</li>
 <li>Power9-optimized instruction scheduling in GCC.</li>
 <li>Requires at least Power8 for ppc64le.</li>
 <li>Power8 Transactional Memory enablement.</li>
@@ -12,6 +13,61 @@
 <h3>Debian 10 (buster) end of support</h3>
 <p>Debian 10 (buster) reached EOL in August 2022. Advance Toolchain packages won't be provided for Debian 10 (buster) with Advance Toolchain 15.0-4 and later. </p>
 
+<h3>New features in 15.0-6</h3>
+<ul>
+  <li>GCC provides:
+  <ul>
+    <li>Version 11.4, see the <a href="https://gcc.gnu.org/gcc-11/changes.html">release notes</a> for details.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100607">ICE with SELECT RANK</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103506">ICE in gfc_free_namespace, at fortran/symbol.c:4039 since r10-2798-ge68a35ae4a65d2b3</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105325">power10: Error: operand out of range</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107397">ICE in gfc_arith_plus, at fortran/arith.cc:654</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108842">Cannot use enum array with -fno-druntime</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109932">ICE in in extract_insn, at recog.cc:2791 on ppc64le with -mno-vsx</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110011">-mfull-toc (-mfp-in-toc) yields incorrect _Float128 constants on power9</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110288">Regression: segfault in findloc with allocatable array of allocatable characters</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110516">core.volatile.volatileLoad discarded if result is unused</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110585">ICE in gfc_compare_expr for findloc with complex literal array</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110658">MINVAL/MAXVAL and deferred-length character arrays</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110741">vec_ternarylogic intrinsic generates incorrect code on POWER10 target when compiled with GCC</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111367">Error: operand out of range (0x1391c is not between 0xffffffffffff8000 and 0x7fff)</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111837">Out of bounds access with optimization inside io-implied-do-control</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66005">libgomp make check time is excessive</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95947">PACK intrinsic returns blank strings when an allocatable character array with allocatable length is used</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96024">ICE in mio_name_expr_t, at fortran/module.c:2159</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96762">ICE in extract_insn, at recog.c:2294 (error: unrecognizable insn)</a>.</li>
+  </ul></li>
+  <li>GNU C Library provides:
+  <ul>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=20975">Deferred cancellation triggers in __check_pf and looses lock leading to deadlock.</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28852">getaddrinfo leaks memory with AI_ALL</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28931">hosts lookup broken for SUCCESS=CONTINUE and SUCCESS=MERGE (CVE-2023-4813)</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=30745">Slight bug in cache info codes for x86</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=30842">Stack read overflow in getaddrinfo in no-aaaa mode (CVE-2023-4527)</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=30843">potential use-after-free in getcanonname (CVE-2023-4806)</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=30884">Memory leak in getaddrinfo after fix for bug 30843 (CVE-2023-5156)</a>.</li>
+  </ul></li>
+  <li>OpenSSL provides:
+  <ul>
+    <li>Version 1.1.1w, see the <a href="https://www.openssl.org/news/openssl-1.1.1-notes.html">release notes</a> for details.</li>
+  </ul></li>
+  <li>Python provides:
+  <ul>
+    <li>Version 3.9.18, see the <a href="https://www.python.org/downloads/release/python-3918/">release notes</a> for details.</li>
+  </ul></li>
+  <li>Userspace RCU provides:
+  <ul>
+    <li>Fix urcu-bp: misaligned reader accesses.</li>
+    <li>rculfhash: Use caa_container_of_check_null in cds_lfht_entry.</li>
+    <li>compiler.h: Introduce caa_container_of_check_null.</li>
+    <li>compiler.h: Introduce caa_unqual_scalar_typeof.</li>
+    <li>Avoid calling caa_container_of on NULL pointer in cds_lfht macros.</li>
+  </ul></li>
+</ul>
+
+<a name="previous"></a>
+<h2>Previous releases</h2>
+
 <h3>New features in 15.0-5</h3>
 <ul>
   <li>GCC provides:
@@ -78,9 +134,6 @@ <h3>New features in 15.0-5</h3>
   </ul></li>
 </ul>
 
-<a name="previous"></a>
-<h2>Previous releases</h2>
-
 <h3>New features in 15.0-4</h3>
 <ul>
   <li>GCC provides:
diff --git a/docs/advance-toolchain-linux-on-power b/docs/advance-toolchain-linux-on-power
index 497d43471..c56a9cec7 100644
--- a/docs/advance-toolchain-linux-on-power
+++ b/docs/advance-toolchain-linux-on-power
@@ -146,7 +146,7 @@ function myFunction() {
 </div>
 
 <div class="ibm-band-fluid ibm-flex ibm-padding-top-2  ibm-padding-bottom-1">
-<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 </div>
 <!-- start main content -->
 
diff --git a/docs/advtool-cross-compilers b/docs/advtool-cross-compilers
index 8aa7dc9d6..9f11a86c1 100644
--- a/docs/advtool-cross-compilers
+++ b/docs/advtool-cross-compilers
@@ -139,7 +139,7 @@
 </div>
 
 <div class="ibm-band-fluid ibm-flex ibm-padding-top-2  ibm-padding-bottom-1">
-<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 </div>
 
 <div class="ibm-band-fluid ibm-flex ibm-nospacing ibm-flex--wrap">
diff --git a/docs/advtool-faq b/docs/advtool-faq
index 3aa731deb..521b5005b 100644
--- a/docs/advtool-faq
+++ b/docs/advtool-faq
@@ -134,7 +134,7 @@
 <!--Start of vertical tabs -->
 
 <div class="ibm-band-fluid ibm-flex ibm-padding-top-2  ibm-padding-bottom-1">
-<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 </div>
 
 <div class="ibm-graphic-tabs ibm-graphic-tabs--colored ibm-vertical-tabs ibm-padding-bottom-3" data-remembertab="false" data-widget="dyntabs"><!-- Tabs here: -->
diff --git a/docs/advtool-install b/docs/advtool-install
index 0860a97bc..47208b050 100644
--- a/docs/advtool-install
+++ b/docs/advtool-install
@@ -140,7 +140,7 @@ function myFunction() {
 </div>
 
 <div class="ibm-band-fluid ibm-flex ibm-padding-top-2  ibm-padding-bottom-1">
-<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 </div>
 
 <div class="ibm-band-fluid ibm-flex ibm-nospacing ibm-flex--wrap ibm-padding-top-2 ibm-padding-bottom-1"><!--Get started-->
diff --git a/docs/advtool-updates b/docs/advtool-updates
index baa1d1690..6a3f9f980 100644
--- a/docs/advtool-updates
+++ b/docs/advtool-updates
@@ -142,7 +142,7 @@ function myFunction() {
 
 <div class="ibm-band-fluid ibm-flex  ibm-flex--wrap ibm-padding-top-2 ibm-padding-bottom-1">
 <div class="ibm-col-12-12">
-<p class="ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 &nbsp;
 
 <p class="ibm-h4">We frequently release updates to each of the Advance Toolchain versions. Find links to the release notes (from year 2020) for the updates, newest to oldest, in the following table.</p>
@@ -167,6 +167,10 @@ function myFunction() {
 	<thead>
 	</thead>
 	<tbody>
+		<tr>
+			<td><a href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Advance Toolchain 15.0-6</a></td>
+			<td>11/17/2023</td>
+		</tr>
 		<tr>
 			<td><a href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Advance Toolchain 17.0-1</a></td>
 			<td>10/20/2023</td>
diff --git a/docs/advtool-usage b/docs/advtool-usage
index a32c6121c..4a269d9fe 100644
--- a/docs/advtool-usage
+++ b/docs/advtool-usage
@@ -143,7 +143,7 @@ document.getElementById('toggle_btn').addEventListener('click',function(e){
 <!--Start of vertical tabs -->
 
 <div class="ibm-band-fluid ibm-flex ibm-padding-top-2  ibm-padding-bottom-1">
-<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 17.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at17.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-6 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-6" target="_blank">Learn more</a></p>
 </div>
 
 <div class="ibm-graphic-tabs ibm-graphic-tabs--colored ibm-vertical-tabs" data-remembertab="false" data-widget="dyntabs"><!-- Tabs here: -->