diff --git a/configs/15.0/base.mk b/configs/15.0/base.mk
index a2f45e09d..84165b576 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 := 4
-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 2f0c6b58e..f67ddd093 100644
--- a/configs/15.0/release_notes/relfixes.html
+++ b/configs/15.0/release_notes/relfixes.html
@@ -12,6 +12,117 @@
 <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 15.0-4</h3>
+<ul>
+  <li>GCC provides:
+  <ul>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100029">ICE on subroutine call with allocatable polymorphic assumed-rank argument</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100040">Wrong code with intent out assumed-rank allocatable</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100097">Unlimited polymorphic pointers and allocatables have incorrect rank</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100098">Polymorphic pointers and allocatables have incorrect rank</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100132">Optimization breaks pointer association</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100136">ICE, regression, using flag -fcheck=pointer</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100245">ICE on automatic reallocation</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101322">ICE in copy_to_mode_reg, at explow.c:651</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102059">Incorrect always_inline diagnostic in LTO mode with #pragma GCC target(&quot;cpu=power10&quot;)</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103137">ICE in gfc_simplify_transpose, at fortran/simplify.c:8181 since r12-4967-gbcf3728abe848888</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103138">ICE in gfc_simplify_cshift, at fortran/simplify.c:2139 since r12-4967-gbcf3728abe848888</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103197">ppc inline expansion of memcpy/memmove should not use lxsibzx/stxsibx for a single byte</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103413">ICE: Invalid expression in gfc_element_size since r10-2083-g8dc63166e0b85954</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103504">ICE in get_sym_storage_size, at fortran/interface.c:2800</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103693">ICE in gfc_array_dimen_size(): Bad EXPR_ARRAY expr since r12-4967-gbcf3728abe848888</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103694">ICE in gfc_conv_expr_op, at fortran/trans-expr.c:3882 since r12-3993-gb19bbfb148250536</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104313">ICE verify_gimple failed with -ff2c since r10-2279-ge0af8f52b10385d8</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104829">Pure 32-bit PowerPC build broken</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104849">ICE in find_array_section, at fortran/expr.cc:1616</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105230">ICE in find_array_section, at fortran/expr.cc:1634</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105243">ICE in next_char, at fortran/io.cc:160</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105252">ICE: in cmp_cst, at analyzer/svalue.cc:309 with -O -fanalyzer -fnon-call-exceptions since r12-1931-ge61ffa201403e381</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105331">-Wmaybe-uninitialized warning on va_arg with double _Complex on va_list pointer</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105349">gcc.target/powerpc/bswap-brw.c fails after r12-8221</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105365">ICE: in cmp_cst, at analyzer/svalue.cc:309 with -fanalyzer since r12-2337-g33255ad3ac14e395</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105366">ICE: in cmp_cst, at analyzer/svalue.cc:309 with -O -fanalyzer since r11-4511-gf635f0ce87d687b1</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105396">missed stack-buffer-overflow by -O0</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105633">ICE in find_array_section, at fortran/expr.cc:1582</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105691">Incorrect calculation of INDEX(str1,str2) at compile time</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105729">False positive UBsan &quot;reference binding to null pointer of type&quot; when evaluating array indexing which throws exception</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105732">internal compiler error: unspellable token PADDING</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105813">ICE in gfc_simplify_unpack, at fortran/simplify.cc:8490</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105954">ICE in gfc_element_size, at fortran/target-memory.cc:132</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106016">crash with attempt to initialize array of MMA accumulators</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106017">No array-to-pointer conversion for MMA accumulator</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106091">during RTL pass: swaps ICE: verify_flow_info failed: missing REG_EH_REGION note at the end of bb 69 with -fnon-call-exceptions</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106121">ICE in gfc_simplify_extends_type_of, at fortran/simplify.cc:3109</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106334">lto -g ICE in dwarf2out_register_external_die at dwarf2out.cc:6072</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106345">Some ppc64le tests fail with -mcpu=power9 -mtune=power9</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106540">lto -g ICE in dwarf2out_register_external_die at dwarf2out.cc:6076</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106817">clobber ordering problem when an actual intent(in) argument depends on the value of an intent(out) argument</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106857">ICE in gfc_simplify_pack, at fortran/simplify.cc:6438 since r12-4278-g74ccca380cde5e79</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106981">ICE in decompose, at wide-int.h:984 with '#pragma omp/acc atomic capture'</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106985">ICE in gfc_simplify_expr, at fortran/expr.cc:2290</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106986">ICE in simplify_findloc_nodim, at fortran/simplify.cc:5675</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107054">ICE in gfc_simplify_unpack, at fortran/simplify.cc:8461</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107576">ICE in gfc_conv_procedure_call, at fortran/trans-expr.cc:6193</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107592">ICE: gdc segfault on label continue</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82868">ICE in generate_coarray_sym_init, at fortran/trans-decl.c:5203</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96072">ICE: Segmentation fault (in add_reg_note)</a>.</li>
+    <li>Fix for <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97498">#pragma GCC diagnostic ignored &quot;-Wunused-function&quot; inconsistent</a>.</li>
+  </ul></li>
+  <li>GNU C Library provides:
+  <ul>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=12154">Cannot resolve hosts which have wildcard aliases</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=15333">Use 64-bit stat functions in installed programs</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=16448">adapt stap-prep for el7</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=24816">nss/tst-nss-files-hosts-long fails when no interface has AF_INET6 address (ie docker)</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=26779">benign use after realloc at localealias.c:329</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=27054">pthread_atfork handlers that call pthread_atfork deadlock</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=27087">PowerPC: Redefinition error with Clang from IEEE redirection headers</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28439">-Wformat-overflow in resolv/res_query.c</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28470">Buffer read overrun in regular expression searching</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28752">Segfault in getpwuid when stat fails</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28771">%ebx optimization macros are incompatible with .altmacro in Systemtap probes</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=28846">CMSG_NXTHDR may trigger -Wstrict-overflow warning</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29035">Output of mktime with latest gcc and glibc differs with their older version when is_dst flag set</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29127">Incomplete backport causes tst-{strncmp,wcsncmp}-rtm to fail</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29162">string.h syntactic error: include/bits/string_fortified.h:110: error: expected ',' or ';' before '__fortified_attr_access'</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29197">__strncpy_power9() uses uninitialised register vs18 value for filling after \0</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29208">fpathconf(_PC_ASYNC_IO) is not y2038 aware</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29214">pthread_setcanceltype fails to set type</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29225">Mistyped define statement in socket/sys/socket.h in line 184</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29234">Bug in rawmemchr-avx2 can return incorrect result</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29265">mbstowcs with NULL dst throws an incorrect warning (glibc == 2.35, gcc=12.0.1)</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29279">undefined reference to `mbstowcs_chk' after 464d189b9622932a75302290625de84931656ec0</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29304">mq_timedreceive does not handle 64 bit syscall return correct for !__ASSUME_TIME64_SYSCALLS</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29305">Inefficient buffer space usage in nss_dns for gethostbyname and other functions</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29415">getaddrinfo with AI_ADDRCONFIG returns addresses with wrong family</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29446">__dlopen now ignores dl_caller argument in static mode</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29528">__libc_early_init not called after dlmopen that reuses namespace</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29591">wcsnlen length can overflow in page cross case.</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29600">dlmopen hangs after loading certain libraries</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29611">Optimized AVX2 string functions unconditionally use BMI2 instructions</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29657">Incorrect struct stat for 64-bit time on linux/generic platforms</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29771">Restore IPC_64 support in sysvipc *ctl functions</a>.</li>
+    <li>Fix for <a href="https://sourceware.org/bugzilla/show_bug.cgi?id=29776">elf/tst-tlsopt-powerpc fails when compiled with -mcpu=power10</a>.</li>
+  </ul></li>
+  <li>Userspace RCU provides:
+  <ul>
+    <li>Version 0.13.2, see the <a href="https://github.com/urcu/userspace-rcu/blob/v0.13.2/ChangeLog">release notes</a> for details.</li>
+  </ul></li>
+  <li>OpenSSL provides:
+  <ul>
+    <li>Version 1.1.1s, see the <a href="https://www.openssl.org/news/openssl-1.1.1-notes.html">release notes</a> for details.</li>
+    <li>Fix a memory leak in rsa_priv_encode.</li>
+    <li>Fix the ceiling on how much encryption growth we can have.</li>
+  </ul></li>
+  <li>Python provides:
+  <ul>
+    <li>Version 3.9.16, see the <a href="https://www.python.org/downloads/release/python-3916/">release notes</a> for details.</li>
+  </ul></li>
+</ul>
+
+<a name="previous"></a>
+<h2>Previous releases</h2>
+
 <h3>New features in 15.0-3</h3>
 <ul>
   <li>GCC provides:
@@ -75,9 +186,6 @@ <h3>New features in 15.0-3</h3>
   </ul></li>
 </ul>
 
-<a name="previous"></a>
-<h2>Previous releases</h2>
-
 <h3>New features in 15.0-2</h3>
 <ul>
   <li>Advance Toolchain provides:
diff --git a/docs/advance-toolchain-linux-on-power b/docs/advance-toolchain-linux-on-power
index db4769d95..49fcd6cb1 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" target="_blank">Learn more</a></p>
 </div>
 <!-- start main content -->
 
diff --git a/docs/advtool-cross-compilers b/docs/advtool-cross-compilers
index eac0463dd..79082d882 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" 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 6b5281e81..3c75447a3 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" 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 74468e903..f916dc74a 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" 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 877a9eae8..43e6eef75 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" 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/at15.0-4" target="_blank">Advance Toolchain 15.0-4</a></td>
+			<td>02/03/2023</td>
+		</tr>
 		<tr>
 			<td><a href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Advance Toolchain 16.0-1</a></td>
 			<td>11/25/2022</td>
diff --git a/docs/advtool-usage b/docs/advtool-usage
index 5281bd7d3..6ad8c19e9 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 16.0-1 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at16.0-1" target="_blank">Learn more</a></p>
+<p class="custom-padding-left-12px ibm-h4">IBM Advance Toolchain for Linux on Power 15.0-4 is now available! <a class="ibm-forward-link ibm-inlinelink" href="https://github.com/advancetoolchain/advance-toolchain/releases/tag/at15.0-4" 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: -->