diff --git a/php-install.sh b/php-install.sh
index 4046a1c..cde3181 100644
--- a/php-install.sh
+++ b/php-install.sh
@@ -158,15 +158,36 @@ case $PHP_VERSION in
 esac
 
 case $PHP_VERSION in
-  8.1*|8.2*|8.3*|8.4*|8.5*|8.6*)
+  8.6*)
+    # apcu's latest tagged release (pie/pecl install this) predates the
+    # upstream fix for PHP 8.6's php_verror() signature change, so build
+    # from the default branch instead, same as the other 8.6 workarounds
+    # below.
+    php -m | grep -q '^apcu$' || (
+      git clone --depth=1 https://github.com/krakjoe/apcu.git /usr/src/apcu &&
+      cd /usr/src/apcu &&
+      phpize && ./configure --enable-apcu && make -j"$(nproc)" && make install &&
+      echo "extension=apcu.so" > /usr/local/etc/php/conf.d/apcu.ini
+    )
+    rm -rf /usr/src/apcu
+    ;;
+  8.1*|8.2*|8.3*|8.4*|8.5*)
     pie install apcu/apcu
+    ;;
+  *)
+    yes | pecl install apcu
+    ;;
+esac
+
+case $PHP_VERSION in
+  8.1*|8.2*|8.3*|8.4*|8.5*|8.6*)
     pie install rdkafka/rdkafka
     pie install pecl/yaml
     pie install pecl/uuid
     pie install msgpack/msgpack-php
     ;;
   *)
-    yes | pecl install apcu rdkafka yaml uuid msgpack
+    yes | pecl install rdkafka yaml uuid msgpack
     ;;
 esac
 
@@ -372,7 +393,7 @@ docker-php-ext-install gmp ldap xsl mysqli calendar gd pdo_mysql pdo_pgsql zip b
 
 case $PHP_VERSION in
   8.1*|8.2*|8.3*|8.4*|8.5*|8.6*)
-    echo "rdkafka and apcu were already enabled by pie for PHP $PHP_VERSION"
+    echo "rdkafka was already enabled by pie, and apcu by pie or its own install step, for PHP $PHP_VERSION"
     ;;
   *)
     docker-php-ext-enable rdkafka apcu
diff --git a/unstable-tag b/unstable-tag
index 8a5b208..fb100c5 100644
--- a/unstable-tag
+++ b/unstable-tag
@@ -1 +1 @@
-8.6.0alpha2
+8.6.0alpha3