diff --git a/.github/workflows/build_helper.sh b/.github/workflows/build_helper.sh
index d7136f7..7bca12b 100755
--- a/.github/workflows/build_helper.sh
+++ b/.github/workflows/build_helper.sh
@@ -13,7 +13,7 @@
 # These tools were recreated to reduce the number of fixes and
 # reduce the workload of developers when there is a change in
 # the project configuration.
-# 
+#
 # For the full copyright and license information, please view
 # the license file that was distributed with this source code.
 #
@@ -418,9 +418,47 @@ run_publish_package()
 			PRNERR "Token for uploading to packagecloud.io is not specified."
 			return 1
 		fi
-		if ! PACKAGECLOUD_TOKEN="${CI_PACKAGECLOUD_TOKEN}" /bin/sh -c "package_cloud push ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG} ${SRCTOP}/${PKG_OUTPUT_DIR}/*.${PKG_EXT}"; then
-			PRNERR "Failed to publish *.${PKG_EXT} packages to ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG}"
-			return 1
+
+		# [NOTE]
+		# The Ruby environment of some OS uses RVM (Ruby Version Manager) and requires a Bash shell environment.
+		#
+		if [ "${IS_OS_DEBIAN}" -eq 1 ] && echo "${CI_OSTYPE}" | sed -e 's#:##g' | grep -q -i -e 'debian10' -e 'debianbuster'; then
+			#
+			# Case for Debian 10(buster)
+			#
+			{
+				#
+				# Create bash script for run package_cloud command, because using RVM(Ruby Version Manager).
+				#
+				echo '#!/bin/bash'
+				echo ''
+				echo 'source /etc/profile.d/rvm.sh'
+				echo ''
+				echo 'if ! '"PACKAGECLOUD_TOKEN=${CI_PACKAGECLOUD_TOKEN} package_cloud push ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG} ${SRCTOP}/${PKG_OUTPUT_DIR}/*.${PKG_EXT}; then"
+				echo '	exit 1'
+				echo 'fi'
+				echo ''
+				echo 'exit 0'
+			} > /tmp/run_package_cloud.sh
+			chmod +x /tmp/run_package_cloud.sh
+
+			#
+			# Run bash script
+			#
+			if ({ RUNCMD /tmp/run_package_cloud.sh || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+				PRNERR "Failed to publish *.${PKG_EXT} packages to ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG}"
+				rm -f /tmp/run_package_cloud.sh
+				return 1
+			fi
+			rm -f /tmp/run_package_cloud.sh
+		else
+			#
+			# Case for other than Debian 10(buster)
+			#
+			if ! PACKAGECLOUD_TOKEN="${CI_PACKAGECLOUD_TOKEN}" /bin/sh -c "package_cloud push ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG} ${SRCTOP}/${PKG_OUTPUT_DIR}/*.${PKG_EXT}"; then
+				PRNERR "Failed to publish *.${PKG_EXT} packages to ${CI_PACKAGECLOUD_OWNER}/${CI_PACKAGECLOUD_PUBLISH_REPO}/${DIST_TAG}"
+				return 1
+			fi
 		fi
 	else
 		PRNINFO "Not need to publish packages"
@@ -1062,11 +1100,11 @@ if [ "${CI_DO_PUBLISH}" -eq 1 ]; then
 			PRNERR "Failed to install SCL packages"
 			exit 1
 		fi
-		if ({ RUNCMD "${INSTALLER_BIN}" "${INSTALL_CMD}" "${INSTALL_CMD_ARG}" "${INSTALL_AUTO_ARG}" "${INSTALL_QUIET_ARG}" rh-ruby24 rh-ruby24-ruby-devel rh-ruby24-rubygem-rake || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+		if ({ RUNCMD "${INSTALLER_BIN}" "${INSTALL_CMD}" "${INSTALL_CMD_ARG}" "${INSTALL_AUTO_ARG}" "${INSTALL_QUIET_ARG}" rh-ruby26 rh-ruby26-ruby-devel rh-ruby26-rubygem-rake || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
 			PRNERR "Failed to install ruby packages"
 			exit 1
 		fi
-		. /opt/rh/rh-ruby24/enable
+		. /opt/rh/rh-ruby26/enable
 
 		if ({ RUNCMD "${GEM_BIN}" "${GEM_INSTALL_CMD}" package_cloud || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
 			PRNERR "Failed to install packagecloud.io upload tools"
@@ -1082,9 +1120,128 @@ if [ "${CI_DO_PUBLISH}" -eq 1 ]; then
 			exit 1
 		fi
 
+	elif [ "${IS_OS_ROCKY}" -eq 1 ] && echo "${CI_OSTYPE}" | sed -e 's#:##g' | grep -q -i -e 'rockylinux8' -e 'rocky8'; then
+		#
+		# Case for Rocky Linux 8 (default ruby 2.5)
+		#
+
+		#
+		# Switch ruby module
+		#
+		if ({ RUNCMD "${INSTALLER_BIN}" module "${INSTALL_AUTO_ARG}" reset ruby || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to reset ruby module"
+			exit 1
+		fi
+		if ({ RUNCMD "${INSTALLER_BIN}" module "${INSTALL_AUTO_ARG}" install ruby:2.6 || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to install ruby 2.6 module"
+			exit 1
+		fi
+		if ({ RUNCMD "${INSTALLER_BIN}" module "${INSTALL_AUTO_ARG}" enable ruby:2.6 || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to enable ruby 2.6 module"
+			exit 1
+		fi
+		if ({ RUNCMD "${INSTALLER_BIN}" module "${INSTALL_AUTO_ARG}" update ruby:2.6 || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to update ruby 2.6 module"
+			exit 1
+		fi
+
+		#
+		# Install package_cloud tool
+		#
+		if ({ RUNCMD "${GEM_BIN}" "${GEM_INSTALL_CMD}" package_cloud || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to install packagecloud.io upload tools"
+			exit 1
+		fi
+
+	elif [ "${IS_OS_DEBIAN}" -eq 1 ] && echo "${CI_OSTYPE}" | sed -e 's#:##g' | grep -q -i -e 'debian10' -e 'debianbuster'; then
+		#
+		# Case for Debian 10/buster (default ruby 2.5)
+		#
+
+		#
+		# Set RVM(Ruby Version Manager) and install Ruby 2.6 and package_cloud
+		#
+		# [NOTE]
+		# Install Ruby2.6 using RVM tools.
+		# Installation and running RVM tools must be done in Bash.
+		# This set of installations will create a Bash script and run it.
+		#
+		# The script does the following:
+		# First, we need to install the GPG key before installing RVM.
+		# This is done with one of the following commands:
+		#
+		#	sudo gpg --keyserver hkp://keyserver.ubuntu.com --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
+		#		or
+		#	command curl -sSL https://rvm.io/mpapis.asc | sudo gpg --import -
+		#	command curl -sSL https://rvm.io/pkuczynski.asc | sudo gpg --import -
+		#
+		# After that, install RVM installation, RVM environment settings, Ruby2.6 installation, and package_cloud tools.
+		#
+		# [NOTE]
+		# The RVM installation requires running from a bash shell.
+		# So create a Bash script and run it.
+		{
+			echo '#!/bin/bash'
+			echo ''
+			echo 'if ! curl -sSL https://rvm.io/mpapis.asc | gpg --import - 2>&1; then'
+			echo '	echo "Failed to run [ curl -sSL https://rvm.io/mpapis.asc | gpg --import - ] command."'
+			echo '	exit 1'
+			echo 'fi'
+			echo 'if ! curl -sSL https://rvm.io/pkuczynski.asc | gpg --import - 2>&1; then'
+			echo '	echo "Failed to run [ curl -sSL https://rvm.io/pkuczynski.asc | gpg --import - ] command."'
+			echo '	exit 1'
+			echo 'fi'
+			echo ''
+			echo 'if ! curl -sSL https://get.rvm.io | bash -s stable --ruby 2>&1; then'
+			echo '	echo "Failed to install RVM tool."'
+			echo '	exit 1'
+			echo 'fi'
+			echo ''
+			echo 'if [ ! -f /etc/profile.d/rvm.sh ]; then'
+			echo '	echo "Not found /etc/profile.d/rvm.sh file."'
+			echo '	exit 1'
+			echo 'fi'
+			echo 'source /etc/profile.d/rvm.sh'
+			echo ''
+			echo 'if ! rvm get stable --autolibs=enable 2>&1; then'
+			echo '	echo "Failed to get/update RVM stable."'
+			echo '	exit 1'
+			echo 'fi'
+			echo 'if ! usermod -a -G rvm root 2>&1; then'
+			echo '	echo "Failed to add rvm user to root group."'
+			echo '	exit 1'
+			echo 'fi'
+			echo 'if ! rvm install ruby-2.6 2>&1; then'
+			echo '	echo "Failed to install ruby 2.6."'
+			echo '	exit 1'
+			echo 'fi'
+			echo 'if ! rvm --default use ruby-2.6 2>&1; then'
+			echo '	echo "Failed to set ruby 2.6 as default."'
+			echo '	exit 1'
+			echo 'fi'
+			echo ''
+			echo 'if ! '"${GEM_BIN} ${GEM_INSTALL_CMD} package_cloud 2>&1; then"
+			echo '	echo "Failed to install packagecloud.io upload tools"'
+			echo '	exit 1'
+			echo 'fi'
+			echo ''
+			echo 'exit 0'
+		} > /tmp/rvm_setup.sh
+		chmod +x /tmp/rvm_setup.sh
+
+		#
+		# Run bash script
+		#
+		if ({ RUNCMD /tmp/rvm_setup.sh || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
+			PRNERR "Failed to set up RVM."
+			rm -f /tmp/rvm_setup.sh
+			exit 1
+		fi
+		rm -f /tmp/rvm_setup.sh
+
 	else
 		#
-		# Case for other than CentOS
+		# Case for other than CentOS / Alpine / Debian 10 / Rocky Linux 8
 		#
 		if ({ RUNCMD "${GEM_BIN}" "${GEM_INSTALL_CMD}" rake package_cloud || echo > "${PIPEFAILURE_FILE}"; } | sed -e 's/^/    /g') && rm "${PIPEFAILURE_FILE}" >/dev/null 2>&1; then
 			PRNERR "Failed to install packagecloud.io upload tools"
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4761a16..41fdfdc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -63,15 +63,14 @@ jobs:
         container:
           - ubuntu:22.04
           - ubuntu:20.04
-          - ubuntu:18.04
           - debian:bookworm
           - debian:bullseye
           - debian:buster
           - rockylinux:9
           - rockylinux:8
           - centos:centos7
+          - fedora:38
           - fedora:37
-          - fedora:36
           - alpine:3.18
 
     container:
diff --git a/.github/workflows/ostypevars.sh b/.github/workflows/ostypevars.sh
index 7cee00c..6ada4eb 100644
--- a/.github/workflows/ostypevars.sh
+++ b/.github/workflows/ostypevars.sh
@@ -122,20 +122,6 @@ elif [ "${CI_OSTYPE}" = "ubuntu:20.04" ] || [ "${CI_OSTYPE}" = "ubuntu:focal" ];
 	PKG_EXT="deb"
 	IS_OS_UBUNTU=1
 
-elif [ "${CI_OSTYPE}" = "ubuntu:18.04" ] || [ "${CI_OSTYPE}" = "ubuntu:bionic" ]; then
-	DIST_TAG="ubuntu/bionic"
-	INSTALL_PKG_LIST="git autoconf autotools-dev gcc g++ make gdb dh-make fakeroot dpkg-dev devscripts libtool pkg-config ruby-dev rubygems rubygems-integration procps libfullock-dev libgcrypt20-dev"
-	INSTALLER_BIN="apt-get"
-	UPDATE_CMD="update"
-	UPDATE_CMD_ARG=""
-	INSTALL_CMD="install"
-	INSTALL_CMD_ARG=""
-	INSTALL_AUTO_ARG="-y"
-	INSTALL_QUIET_ARG="-qq"
-	PKG_OUTPUT_DIR="debian_build"
-	PKG_EXT="deb"
-	IS_OS_UBUNTU=1
-
 elif [ "${CI_OSTYPE}" = "debian:12" ] || [ "${CI_OSTYPE}" = "debian:bookworm" ]; then
 	DIST_TAG="debian/bookworm"
 	INSTALL_PKG_LIST="git autoconf autotools-dev gcc g++ make gdb dh-make fakeroot dpkg-dev devscripts libtool pkg-config ruby-dev rubygems rubygems-integration procps libfullock-dev libgcrypt20-dev"
@@ -220,7 +206,7 @@ elif [ "${CI_OSTYPE}" = "centos:7" ] || [ "${CI_OSTYPE}" = "centos:centos7" ]; t
 	PKG_EXT="rpm"
 	IS_OS_CENTOS=1
 
-elif [ "${CI_OSTYPE}" = "fedora:37" ]; then
+elif [ "${CI_OSTYPE}" = "fedora:38" ]; then
 	DIST_TAG="fedora/37"
 	INSTALL_PKG_LIST="git autoconf automake gcc gcc-c++ gdb make libtool pkgconfig redhat-rpm-config rpm-build ruby-devel rubygems procps libfullock-devel nss-devel"
 	INSTALLER_BIN="dnf"
@@ -234,8 +220,8 @@ elif [ "${CI_OSTYPE}" = "fedora:37" ]; then
 	PKG_EXT="rpm"
 	IS_OS_FEDORA=1
 
-elif [ "${CI_OSTYPE}" = "fedora:36" ]; then
-	DIST_TAG="fedora/36"
+elif [ "${CI_OSTYPE}" = "fedora:37" ]; then
+	DIST_TAG="fedora/37"
 	INSTALL_PKG_LIST="git autoconf automake gcc gcc-c++ gdb make libtool pkgconfig redhat-rpm-config rpm-build ruby-devel rubygems procps libfullock-devel nss-devel"
 	INSTALLER_BIN="dnf"
 	UPDATE_CMD="update"
diff --git a/buildutils/control.in b/buildutils/control.in
index df12686..d3cd5e2 100644
--- a/buildutils/control.in
+++ b/buildutils/control.in
@@ -2,7 +2,7 @@ Source: @PACKAGE_NAME@
 Section: database
 Priority: optional
 Maintainer: @DEV_NAME@ <@DEV_EMAIL@>
-Build-Depends: @DEBHELPER_DEP@, libfullock-dev (>= 1.0.35), libgcrypt20-dev
+Build-Depends: @DEBHELPER_DEP@, libfullock-dev (>= 1.0.55), libgcrypt20-dev
 Depends: ${misc:Depends}
 Standards-Version: 3.9.8
 Homepage: https://@GIT_DOMAIN@/@GIT_ORG@/@GIT_REPO@
@@ -12,7 +12,7 @@ Vcs-Browser: https://@GIT_DOMAIN@/@GIT_ORG@/@GIT_REPO@
 Package: @PACKAGE_NAME@-dev
 Section: devel
 Architecture: amd64
-Depends: ${misc:Depends}, @PACKAGE_NAME@ (= ${binary:Version}), libfullock-dev (>= 1.0.35), libgcrypt20-dev
+Depends: ${misc:Depends}, @PACKAGE_NAME@ (= ${binary:Version}), libfullock-dev (>= 1.0.55), libgcrypt20-dev
 Description: @SHORTDESC@ (development)
  Development package for building with @PACKAGE_NAME@ shared library.
   This package has header files and symbols for it.
@@ -20,6 +20,6 @@ Description: @SHORTDESC@ (development)
 Package: @PACKAGE_NAME@
 Section: database
 Architecture: amd64
-Depends: ${shlibs:Depends}, ${misc:Depends}, libfullock (>= 1.0.35)
+Depends: ${shlibs:Depends}, ${misc:Depends}, libfullock (>= 1.0.55)
 Description: @SHORTDESC@
 @DEBLONGDESC@
diff --git a/buildutils/k2hash.spec.in b/buildutils/k2hash.spec.in
index e9f7742..eeda204 100644
--- a/buildutils/k2hash.spec.in
+++ b/buildutils/k2hash.spec.in
@@ -56,8 +56,8 @@ License: @PKGLICENSE@
 @RPMPKG_GROUP@
 URL: https://@GIT_DOMAIN@/@GIT_ORG@/@PACKAGE_NAME@
 Source0: https://@GIT_DOMAIN@/@GIT_ORG@/@PACKAGE_NAME@/archive/%{gittag}/%{name}-%{version}.tar.gz
-Requires: libfullock%{?_isa} >= 1.0.35
-BuildRequires: git-core gcc-c++ make libtool libfullock-devel >= 1.0.35 nss-devel
+Requires: libfullock%{?_isa} >= 1.0.55
+BuildRequires: git-core gcc-c++ make libtool libfullock-devel >= 1.0.55 nss-devel
 
 %description
 @LONGDESC@
@@ -110,7 +110,7 @@ rm -rf %{buildroot}
 #
 %package devel
 Summary: @SHORTDESC@ (development)
-Requires: %{name}%{?_isa} = %{version}-%{release}, libfullock-devel%{?_isa} >= 1.0.35, nss-devel
+Requires: %{name}%{?_isa} = %{version}-%{release}, libfullock-devel%{?_isa} >= 1.0.55, nss-devel
 
 %description devel
 Development package for building with @PACKAGE_NAME@ shared library.
diff --git a/configure.ac b/configure.ac
index aa684fd..14cc18f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -273,7 +273,7 @@ AC_ARG_ENABLE(check-depend-libs,
 	esac]
 )
 AS_IF([test ${check_depend_libs} = 1], [AC_MSG_RESULT(yes)], [AC_MSG_RESULT(no)])
-AS_IF([test ${check_depend_libs} = 1], [PKG_CHECK_MODULES([fullock], [libfullock >= 1.0.35], [], [AC_MSG_ERROR(not found libfullock package)])])
+AS_IF([test ${check_depend_libs} = 1], [PKG_CHECK_MODULES([fullock], [libfullock >= 1.0.55], [], [AC_MSG_ERROR(not found libfullock package)])])
 
 #
 # CFLAGS/CXXFLAGS