diff --git a/app/Dockerfile b/app/Dockerfile
index d0dc729..a92907a 100644
--- a/app/Dockerfile
+++ b/app/Dockerfile
@@ -1,21 +1,21 @@
-FROM alpine:3.14
+FROM alpine:3.16
 EXPOSE 9000/tcp
 
 ENV SCRIPT_ROOT=/opt/tt-rss
 
-RUN apk add --no-cache dcron php8 php8-fpm \
-	php8-pdo php8-gd php8-pgsql php8-pdo_pgsql \
-	php8-mbstring php8-intl php8-xml php8-curl \
-	php8-session php8-tokenizer php8-dom php8-fileinfo php8-ctype \
-	php8-json php8-iconv php8-pcntl php8-posix php8-zip php8-exif \
-	php8-openssl git postgresql-client sudo php8-pecl-xdebug rsync && \
-	sed -i 's/\(memory_limit =\) 128M/\1 256M/' /etc/php8/php.ini && \
+RUN apk add --no-cache dcron php81 php81-fpm \
+	php81-pdo php81-gd php81-pgsql php81-pdo_pgsql \
+	php81-mbstring php81-intl php81-xml php81-curl \
+	php81-session php81-tokenizer php81-dom php81-fileinfo php81-ctype \
+	php81-json php81-iconv php81-pcntl php81-posix php81-zip php81-exif \
+	php81-openssl git postgresql-client sudo php81-pecl-xdebug rsync && \
+	sed -i 's/\(memory_limit =\) 128M/\1 256M/' /etc/php81/php.ini && \
 	sed -i -e 's/^listen = 127.0.0.1:9000/listen = 9000/' \
 		-e 's/;\(clear_env\) = .*/\1 = no/i' \
 		-e 's/^\(user\|group\) = .*/\1 = app/i' \
 		-e 's/;\(php_admin_value\[error_log\]\) = .*/\1 = \/tmp\/error.log/' \
 		-e 's/;\(php_admin_flag\[log_errors\]\) = .*/\1 = on/' \
-			/etc/php8/php-fpm.d/www.conf && \
+			/etc/php81/php-fpm.d/www.conf && \
 	mkdir -p /var/www ${SCRIPT_ROOT}/config.d
 
 ADD startup.sh ${SCRIPT_ROOT}
@@ -61,7 +61,7 @@ ENV TTRSS_DB_HOST="db"
 ENV TTRSS_DB_PORT="5432"
 
 ENV TTRSS_MYSQL_CHARSET="UTF8"
-ENV TTRSS_PHP_EXECUTABLE="/usr/bin/php8"
+ENV TTRSS_PHP_EXECUTABLE="/usr/bin/php81"
 ENV TTRSS_PLUGINS="auth_internal, note, nginx_xaccel"
 
 CMD ${SCRIPT_ROOT}/startup.sh
diff --git a/app/startup.sh b/app/startup.sh
index 48a9408..560cc40 100755
--- a/app/startup.sh
+++ b/app/startup.sh
@@ -90,7 +90,7 @@ for d in cache lock feed-icons; do
 done
 
 chown -R $OWNER_UID:$OWNER_GID $DST_DIR \
-	/var/log/php8
+	/var/log/php81
 
 $PSQL -c "create extension if not exists pg_trgm"
 
@@ -104,15 +104,29 @@ fi
 # this was previously generated
 rm -f $DST_DIR/config.php.bak
 
+if [ ! -z "${TTRSS_CORE_DUMPS_ENABLED}" ]; then
+	apk add gdb
+
+	echo "don't forget to enable core dumps on the host:"
+	echo "echo '/tmp/core-%e.%p' > /proc/sys/kernel/core_pattern"
+	echo "then run gdb /usr/sbin/php-fpm81 /tmp/coredump-php-fpm-xyz"
+
+	# enable core dumps
+	sed -i.bak \
+	-e 's/;\(rlimit_core\) = .*/\1 = unlimited/' \
+	-e 's/; *\(process.dumpable\) = .*/\1 = yes/' \
+			/etc/php81/php-fpm.d/www.conf
+fi
+
 if [ ! -z "${TTRSS_XDEBUG_ENABLED}" ]; then
 	if [ -z "${TTRSS_XDEBUG_HOST}" ]; then
 		export TTRSS_XDEBUG_HOST=$(ip ro sh 0/0 | cut -d " " -f 3)
 	fi
 	echo enabling xdebug with the following parameters:
 	env | grep TTRSS_XDEBUG
-	cat > /etc/php8/conf.d/50_xdebug.ini <<EOF
+	cat > /etc/php81/conf.d/50_xdebug.ini <<EOF
 zend_extension=xdebug.so
-xdebug.mode=develop,trace,debug
+xdebug.mode=debug
 xdebug.start_with_request = yes
 xdebug.client_port = ${TTRSS_XDEBUG_PORT}
 xdebug.client_host = ${TTRSS_XDEBUG_HOST}
@@ -120,17 +134,17 @@ EOF
 fi
 
 sed -i.bak "s/^\(memory_limit\) = \(.*\)/\1 = ${PHP_WORKER_MEMORY_LIMIT}/" \
-	/etc/php8/php.ini
+	/etc/php81/php.ini
 
 sed -i.bak "s/^\(pm.max_children\) = \(.*\)/\1 = ${PHP_WORKER_MAX_CHILDREN}/" \
-	/etc/php8/php-fpm.d/www.conf
+	/etc/php81/php-fpm.d/www.conf
 
-sudo -Eu app php8 $DST_DIR/update.php --update-schema=force-yes
+sudo -Eu app php81 $DST_DIR/update.php --update-schema=force-yes
 
 if [ ! -z "$ADMIN_USER_PASS" ]; then
-	sudo -Eu app php8 $DST_DIR/update.php --user-set-password "admin:$ADMIN_USER_PASS"
+	sudo -Eu app php81 $DST_DIR/update.php --user-set-password "admin:$ADMIN_USER_PASS"
 else
-	if sudo -Eu app php8 $DST_DIR/update.php --user-check-password "admin:password"; then
+	if sudo -Eu app php81 $DST_DIR/update.php --user-check-password "admin:password"; then
 		RANDOM_PASS=$(tr -dc A-Za-z0-9 </dev/urandom | head -c 16 ; echo '')
 
 		echo "*****************************************************************************"
@@ -138,17 +152,17 @@ else
 		echo "* If you want to set it manually, use ADMIN_USER_PASS environment variable. *"
 		echo "*****************************************************************************"
 
-		sudo -Eu app php8 $DST_DIR/update.php --user-set-password "admin:$RANDOM_PASS"
+		sudo -Eu app php81 $DST_DIR/update.php --user-set-password "admin:$RANDOM_PASS"
 	fi
 fi
 
 if [ ! -z "$ADMIN_USER_ACCESS_LEVEL" ]; then
-	sudo -Eu app php8 $DST_DIR/update.php --user-set-access-level "admin:$ADMIN_USER_ACCESS_LEVEL"
+	sudo -Eu app php81 $DST_DIR/update.php --user-set-access-level "admin:$ADMIN_USER_ACCESS_LEVEL"
 fi
 
 if [ ! -z "$AUTO_CREATE_USER" ]; then
-	sudo -Eu app /bin/sh -c "php8 $DST_DIR/update.php --user-exists $AUTO_CREATE_USER ||
-		php8 $DST_DIR/update.php --force-yes --user-add \"$AUTO_CREATE_USER:$AUTO_CREATE_USER_PASS:$AUTO_CREATE_USER_ACCESS_LEVEL\""
+	sudo -Eu app /bin/sh -c "php81 $DST_DIR/update.php --user-exists $AUTO_CREATE_USER ||
+		php81 $DST_DIR/update.php --force-yes --user-add \"$AUTO_CREATE_USER:$AUTO_CREATE_USER_PASS:$AUTO_CREATE_USER_ACCESS_LEVEL\""
 fi
 
 rm -f /tmp/error.log && mkfifo /tmp/error.log && chown app:app /tmp/error.log
@@ -158,6 +172,9 @@ rm -f /tmp/error.log && mkfifo /tmp/error.log && chown app:app /tmp/error.log
 unset ADMIN_USER_PASS
 unset AUTO_CREATE_USER_PASS
 
+# cleanup any old lockfiles
+rm -vf -- /var/www/html/tt-rss/lock/*.lock
+
 touch $DST_DIR/.app_is_ready
 
-exec /usr/sbin/php-fpm8 --nodaemonize --force-stderr -R
+exec /usr/sbin/php-fpm81 --nodaemonize --force-stderr -R
diff --git a/app/updater.sh b/app/updater.sh
index 2d96dd6..ca7f113 100755
--- a/app/updater.sh
+++ b/app/updater.sh
@@ -26,7 +26,7 @@ while ! pg_isready -h $TTRSS_DB_HOST -U $TTRSS_DB_USER; do
 done
 
 sed -i.bak "s/^\(memory_limit\) = \(.*\)/\1 = ${PHP_WORKER_MEMORY_LIMIT}/" \
-	/etc/php8/php.ini
+	/etc/php81/php.ini
 
 DST_DIR=/var/www/html/tt-rss
 
@@ -35,4 +35,4 @@ while [ ! -s $DST_DIR/config.php -a -e $DST_DIR/.app_is_ready ]; do
 	sleep 3
 done
 
-sudo -E -u app /usr/bin/php8 /var/www/html/tt-rss/update_daemon2.php
+sudo -E -u app /usr/bin/php81 /var/www/html/tt-rss/update_daemon2.php