diff --git a/release-tool b/release-tool
index adb1e4c61f..b838f87539 100755
--- a/release-tool
+++ b/release-tool
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 #
 # KeePassXC Release Preparation Helper
-# Copyright (C) 2017 KeePassXC team <https://keepassxc.org/>
+# Copyright (C) 2021 KeePassXC team <https://keepassxc.org/>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -17,8 +17,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 printf "\e[1m\e[32mKeePassXC\e[0m Release Preparation Helper\n"
-printf "Copyright (C) 2017 KeePassXC Team <https://keepassxc.org/>\n\n"
+printf "Copyright (C) 2021 KeePassXC Team <https://keepassxc.org/>\n\n"
 
+set -eE -o pipefail
 
 # -----------------------------------------------------------------------
 #                        global default values
@@ -52,7 +53,7 @@ TIMESTAMP_SERVER="http://timestamp.sectigo.com"
 # -----------------------------------------------------------------------
 printUsage() {
     local cmd
-    if [ "" == "$1" ] || [ "help" == "$1" ]; then
+    if [ -z "$1" ] || [ "help" == "$1" ]; then
         cmd="COMMAND"
     elif [ "check" == "$1" ] || [ "merge" == "$1" ] || [ "build" == "$1" ] || [ "gpgsign" == "$1" ] || \
         [ "appsign" == "$1" ] || [ "notarize" == "$1" ] || [ "appimage" == "$1" ] || [ "i18n" == "$1" ]; then
@@ -212,17 +213,17 @@ logError() {
 }
 
 init() {
-    if [ "" == "$RELEASE_NAME" ]; then
+    if [ -z "$RELEASE_NAME" ]; then
         logError "Missing arguments, --version is required!\n"
         printUsage "check"
         exit 1
     fi
 
-    if [ "" == "$TAG_NAME" ]; then
+    if [ -z "$TAG_NAME" ]; then
         TAG_NAME="$RELEASE_NAME"
     fi
 
-    if [ "" == "$SOURCE_BRANCH" ]; then
+    if [ -z "$SOURCE_BRANCH" ]; then
         SOURCE_BRANCH="release/${RELEASE_NAME}"
     fi
 
@@ -285,29 +286,25 @@ checkGitRepository() {
 }
 
 checkReleaseDoesNotExist() {
-    git tag | $GREP -q "^$TAG_NAME$"
-    if [ $? -eq 0 ]; then
+    if ! git tag | $GREP -q "^$TAG_NAME$"; then
         exitError "Release '$RELEASE_NAME' (tag: '$TAG_NAME') already exists!"
     fi
 }
 
 checkWorkingTreeClean() {
-    git diff-index --quiet HEAD --
-    if [ $? -ne 0 ]; then
+    if ! git diff-index --quiet HEAD --; then
         exitError "Current working tree is not clean! Please commit or unstage any changes."
     fi
 }
 
 checkSourceBranchExists() {
-    git rev-parse "$SOURCE_BRANCH" > /dev/null 2>&1
-    if [ $? -ne 0 ]; then
+    if ! git rev-parse "$SOURCE_BRANCH" > /dev/null 2>&1; then
         exitError "Source branch '$SOURCE_BRANCH' does not exist!"
     fi
 }
 
 checkTargetBranchExists() {
-    git rev-parse "$TARGET_BRANCH" > /dev/null 2>&1
-    if [ $? -ne 0 ]; then
+    if ! git rev-parse "$TARGET_BRANCH" > /dev/null 2>&1; then
         exitError "Target branch '$TARGET_BRANCH' does not exist!"
     fi
 }
@@ -318,18 +315,15 @@ checkVersionInCMake() {
     local minor_num="$(echo ${RELEASE_NAME} | cut -f2 -d.)"
     local patch_num="$(echo ${RELEASE_NAME} | cut -f3 -d. | cut -f1 -d-)"
 
-    $GREP -q "${app_name_upper}_VERSION_MAJOR \"${major_num}\"" CMakeLists.txt
-    if [ $? -ne 0 ]; then
+    if ! $GREP -q "${app_name_upper}_VERSION_MAJOR \"${major_num}\"" CMakeLists.txt; then
         exitError "${app_name_upper}_VERSION_MAJOR not updated to '${major_num}' in CMakeLists.txt!"
     fi
 
-    $GREP -q "${app_name_upper}_VERSION_MINOR \"${minor_num}\"" CMakeLists.txt
-    if [ $? -ne 0 ]; then
+    if ! $GREP -q "${app_name_upper}_VERSION_MINOR \"${minor_num}\"" CMakeLists.txt; then
         exitError "${app_name_upper}_VERSION_MINOR not updated to '${minor_num}' in CMakeLists.txt!"
     fi
 
-    $GREP -q "${app_name_upper}_VERSION_PATCH \"${patch_num}\"" CMakeLists.txt
-    if [ $? -ne 0 ]; then
+    if ! $GREP -q "${app_name_upper}_VERSION_PATCH \"${patch_num}\"" CMakeLists.txt; then
         exitError "${app_name_upper}_VERSION_PATCH not updated to '${patch_num}' in CMakeLists.txt!"
     fi
 }
@@ -339,8 +333,7 @@ checkChangeLog() {
         exitError "No CHANGELOG file found!"
     fi
 
-    $GREP -qPzo "## ${RELEASE_NAME} \(\d{4}-\d{2}-\d{2}\)\n" CHANGELOG.md
-    if [ $? -ne 0 ]; then
+    if ! $GREP -qPzo "## ${RELEASE_NAME} \(\d{4}-\d{2}-\d{2}\)\n" CHANGELOG.md; then
         exitError "'CHANGELOG.md' has not been updated to the '${RELEASE_NAME}' release!"
     fi
 }
@@ -350,8 +343,7 @@ checkAppStreamInfo() {
         exitError "No AppStream info file found!"
     fi
 
-    $GREP -qPzo "<release version=\"${RELEASE_NAME}\" date=\"\d{4}-\d{2}-\d{2}\">" share/linux/org.keepassxc.KeePassXC.appdata.xml
-    if [ $? -ne 0 ]; then
+    if ! $GREP -qPzo "<release version=\"${RELEASE_NAME}\" date=\"\d{4}-\d{2}-\d{2}\">" share/linux/org.keepassxc.KeePassXC.appdata.xml; then
         exitError "'share/linux/org.keepassxc.KeePassXC.appdata.xml' has not been updated to the '${RELEASE_NAME}' release!"
     fi
 }
@@ -362,13 +354,11 @@ checkSnapcraft() {
         return
     fi
 
-    $GREP -qPzo "version: ${RELEASE_NAME}" snap/snapcraft.yaml
-    if [ $? -ne 0 ]; then
+    if ! $GREP -qPzo "version: ${RELEASE_NAME}" snap/snapcraft.yaml; then
         exitError "'snapcraft.yaml' has not been updated to the '${RELEASE_NAME}' release!"
     fi
 
-    $GREP -qPzo "KEEPASSXC_BUILD_TYPE=Release" snap/snapcraft.yaml
-    if [ $? -ne 0 ]; then
+    if ! $GREP -qPzo "KEEPASSXC_BUILD_TYPE=Release" snap/snapcraft.yaml; then
         exitError "'snapcraft.yaml' is not set for a release build!"
     fi
 }
@@ -464,7 +454,7 @@ if ! cmdExists realpath; then
 fi
 
 
-trap exitTrap SIGINT SIGTERM
+trap exitTrap SIGINT SIGTERM ERR
 
 # -----------------------------------------------------------------------
 #                             check command
@@ -551,11 +541,10 @@ merge() {
     if [ 0 -ne $? ]; then
         exitError "Updating translations failed!"
     fi
-    git diff-index --quiet HEAD --
-    if [ $? -ne 0 ]; then
+    if ! git diff-index --quiet HEAD --; then
         git add -A ./share/translations/
         logInfo "Committing changes..."
-        if [ "" == "$GPG_GIT_KEY" ]; then
+        if [ -z "$GPG_GIT_KEY" ]; then
             git commit -m "Update translations"
         else
             git commit -m "Update translations" -S"$GPG_GIT_KEY"
@@ -574,7 +563,7 @@ merge() {
     git merge "$SOURCE_BRANCH" --no-ff -m "$COMMIT_MSG" -m "${CHANGELOG}" "$SOURCE_BRANCH" -S"$GPG_GIT_KEY"
 
     logInfo "Creating tag '${TAG_NAME}'..."
-    if [ "" == "$GPG_GIT_KEY" ]; then
+    if [ -z  "$GPG_GIT_KEY" ]; then
         git tag -a "$TAG_NAME" -m "$COMMIT_MSG" -m "${CHANGELOG}" -s
     else
         git tag -a "$TAG_NAME" -m "$COMMIT_MSG" -m "${CHANGELOG}" -s -u "$GPG_GIT_KEY"
@@ -657,7 +646,7 @@ appimage() {
     appdir="$(realpath "$appdir")"
 
     local out="${OUTPUT_DIR}"
-    if [ "" == "$out" ]; then
+    if [ -z "$out" ]; then
         out="."
     fi
     mkdir -p "$out"
@@ -674,12 +663,12 @@ appimage() {
     logInfo "Testing for AppImage tools..."
     local docker_test_cmd
     if [ "" != "$DOCKER_IMAGE" ]; then
-        docker_test_cmd="docker run --rm ${DOCKER_IMAGE}"
+        docker_test_cmd="docker run -it --user $(id -u):$(id -g) --rm ${DOCKER_IMAGE}"
     fi
 
     # Test if linuxdeploy and linuxdeploy-plugin-qt are installed
     # on the system or inside the Docker container
-    if ! ${docker_test_cmd} which ${linuxdeploy} &> /dev/null; then
+    if ! ${docker_test_cmd} which ${linuxdeploy} > /dev/null; then
         logInfo "Downloading linuxdeploy..."
         linuxdeploy="./linuxdeploy"
         linuxdeploy_cleanup="rm -f ${linuxdeploy}"
@@ -688,7 +677,7 @@ appimage() {
         fi
         chmod +x "$linuxdeploy"
     fi
-    if ! ${docker_test_cmd} which ${linuxdeploy_plugin_qt} &> /dev/null; then
+    if ! ${docker_test_cmd} which ${linuxdeploy_plugin_qt} > /dev/null; then
         logInfo "Downloading linuxdeploy-plugin-qt..."
         linuxdeploy_plugin_qt="./linuxdeploy-plugin-qt"
         linuxdeploy_plugin_qt_cleanup="rm -f ${linuxdeploy_plugin_qt}"
@@ -710,49 +699,46 @@ appimage() {
     fi
 
     # Create custom AppRun wrapper
-    cat << EOF > "${out_real}/KeePassXC-AppRun"
+    cat << 'EOF' > "${out_real}/KeePassXC-AppRun"
 #!/usr/bin/env bash
 
-export PATH="\$(dirname \$0)/usr/bin:\${PATH}"
-export LD_LIBRARY_PATH="\$(dirname \$0)/usr/lib:\${LD_LIBRARY_PATH}"
+export PATH="$(dirname $0)/usr/bin:${PATH}"
+export LD_LIBRARY_PATH="$(dirname $0)/usr/lib:${LD_LIBRARY_PATH}"
 
-if [ "\${1}" == "cli" ]; then
+if [ "$1" == "cli" ]; then
     shift
-    exec keepassxc-cli "\$@"
-elif [ "\${1}" == "proxy" ]; then
+    exec keepassxc-cli "$@"
+elif [ "$1" == "proxy" ]; then
     shift
-    exec keepassxc-proxy "\$@"
+    exec keepassxc-proxy "$@"
 elif [ -v CHROME_WRAPPER ] || [ -v MOZ_LAUNCHED_CHILD ]; then
-    exec keepassxc-proxy "\$@"
+    exec keepassxc-proxy "$@"
 else
-    exec keepassxc "\$@"
+    exec keepassxc "$@"
 fi
 EOF
     chmod +x "${out_real}/KeePassXC-AppRun"
 
     # Find .desktop files, icons, and binaries to deploy
     local desktop_file="$(find "$appdir" -name "org.keepassxc.KeePassXC.desktop" | head -n1)"
-    local icon="$(find "$appdir" -name 'keepassxc.png' | $GREP -P 'application/256x256/apps/keepassxc.png$' | head -n1)"
-    local executables="$(IFS=$'\n' find "$appdir" | $GREP -P '/usr/bin/keepassxc[^/]*$' | xargs -i printf " --executable={}")"
+    local icon="$(find "$appdir" -path '*/application/256x256/apps/keepassxc.png' | head -n1)"
+    local executables="$(find "$appdir" -type f -executable -path '*/bin/keepassxc*' -print0 | xargs -0 -i printf " --executable={}")"
 
     logInfo "Collecting libs and patching binaries..."
-    if [ "" == "$DOCKER_IMAGE" ]; then
+    if [ -z "$DOCKER_IMAGE" ]; then
         "$linuxdeploy" --verbosity=${verbosity} --plugin=qt --appdir="$appdir" --desktop-file="$desktop_file" \
-        --custom-apprun="${out_real}/KeePassXC-AppRun" --icon-file="$icon" ${executables} \
-        --library=$(ldconfig -p | $GREP x86-64 | $GREP -oP '/[^\s]+/libgpg-error\.so\.\d+$' | head -n1)
+        --custom-apprun="${out_real}/KeePassXC-AppRun" --icon-file="$icon" ${executables}
     else
-        desktop_file="${desktop_file//${appdir}/\/keepassxc\/AppDir}"
-        icon="${icon//${appdir}/\/keepassxc\/AppDir}"
-        executables="${executables//${appdir}/\/keepassxc\/AppDir}"
-
         docker run --name "$DOCKER_CONTAINER_NAME" --rm \
-            --cap-add SYS_ADMIN --security-opt apparmor:unconfined --device /dev/fuse \
-            -v "${appdir}:/keepassxc/AppDir:rw" \
-            -v "${out_real}:/keepassxc/out:rw" \
+            --cap-add SYS_ADMIN --security-opt apparmor:unconfined --device /dev/fuse -it \
+            -v "${out_real}:${out_real}:rw" \
+            -v "${appdir}:${appdir}:rw" \
+            -w "$out_real" \
+            --user $(id -u):$(id -g) \
             "$DOCKER_IMAGE" \
-            bash -c "cd /keepassxc/out && ${linuxdeploy} --verbosity=${verbosity} --plugin=qt --appdir=/keepassxc/AppDir \
-            --custom-apprun="/keepassxc/out/KeePassXC-AppRun" --desktop-file=${desktop_file} --icon-file=${icon} ${executables} \
-            --library=\$(ldconfig -p | grep x86-64 | grep -oP '/[^\s]+/libgpg-error\.so\.\d+$' | head -n1)"
+            bash -c "${linuxdeploy} --verbosity=${verbosity} --plugin=qt \
+            --appdir='${appdir}' --custom-apprun='${out_real}/KeePassXC-AppRun' \
+            --desktop-file='${desktop_file}' --icon-file='${icon}' ${executables}"
     fi
 
     if [ $? -ne 0 ]; then
@@ -900,7 +886,6 @@ build() {
 
     init
 
-    OUTPUT_DIR="$(realpath "$OUTPUT_DIR")"
     # Resolve appsign key to absolute path if under Windows
     if [[ "${build_key}" && "$(uname -o)" == "Msys" ]]; then
         build_key="$(realpath "${build_key}")"
@@ -930,10 +915,13 @@ build() {
         git checkout "$TAG_NAME" > /dev/null 2>&1
     fi
 
-    logInfo "Creating output directory..."
-    mkdir -p "$OUTPUT_DIR"
+    OUTPUT_DIR="$(realpath "$OUTPUT_DIR")"
+    if  ! ${build_snapshot} && [ -d "$OUTPUT_DIR" ]; then
+        exitError "Output dir '${OUTPUT_DIR}' already exists."
+    fi
 
-    if [ $? -ne 0 ]; then
+    logInfo "Creating output directory..."
+    if ! mkdir -p "$OUTPUT_DIR"; then
         exitError "Failed to create output directory!"
     fi
 
@@ -961,14 +949,6 @@ build() {
         $xz -6 "${OUTPUT_DIR}/${tarball_name}"
     fi
 
-    if ! ${build_snapshot} && [ -e "${OUTPUT_DIR}/build-release" ]; then
-        logInfo "Cleaning existing build directory..."
-        rm -rf "${OUTPUT_DIR}/build-release" 2> /dev/null
-        if [ $? -ne 0 ]; then
-            exitError "Failed to clean existing build directory, please do it manually."
-        fi
-    fi
-
     logInfo "Creating build directory..."
     mkdir -p "${OUTPUT_DIR}/build-release"
     cd "${OUTPUT_DIR}/build-release"
@@ -994,7 +974,7 @@ build() {
     fi
     export CXX="$COMPILER"
 
-    if [ "" == "$DOCKER_IMAGE" ]; then
+    if [ -z "$DOCKER_IMAGE" ]; then
         if [ "$(uname -s)" == "Darwin" ]; then
             # Building on macOS
             export MACOSX_DEPLOYMENT_TARGET
@@ -1068,7 +1048,7 @@ build() {
 
             logInfo "Launching Docker contain to compile snapcraft..."
 
-            sudo docker run --name "$DOCKER_CONTAINER_NAME" --rm \
+            sudo docker run --name "$DOCKER_CONTAINER_NAME" --rm -it --user $(id -u):$(id -g) \
                 -v "$(realpath "$SRC_DIR"):/keepassxc" -w "/keepassxc" \
                 "$DOCKER_IMAGE" snapcraft
         else
@@ -1078,7 +1058,8 @@ build() {
 
             docker run --name "$DOCKER_CONTAINER_NAME" --rm \
                 --cap-add SYS_ADMIN --security-opt apparmor:unconfined --device /dev/fuse \
-                -e "CC=${CC}" -e "CXX=${CXX}" \
+                --user $(id -u):$(id -g) \
+                -e "CC=${CC}" -e "CXX=${CXX}" -it  \
                 -v "$(realpath "$SRC_DIR"):/keepassxc/src:ro" \
                 -v "$(realpath "$OUTPUT_DIR"):/keepassxc/out:rw" \
                 "$DOCKER_IMAGE" \
@@ -1108,7 +1089,7 @@ build() {
             docker_image_flag="-d ${DOCKER_IMAGE}"
             docker_container_name_flag="--container-name ${DOCKER_CONTAINER_NAME}"
         fi
-        appimage "-a" "${OUTPUT_DIR}/KeePassXC.AppDir" "-o" "${OUTPUT_DIR}" \
+        appimage -a "${OUTPUT_DIR}/KeePassXC.AppDir" -o "${OUTPUT_DIR}" \
             ${appsign_flag} ${appsign_key_flag} ${docker_image_flag} ${docker_container_name_flag}
     fi
 
@@ -1376,7 +1357,7 @@ notarize() {
         exit 1
     fi
 
-    if [ "$ac_username" == "" ]; then
+    if [ -z "$ac_username" ]; then
         logError "Missing arguments, --username is required!"
         printUsage "notarize"
         exit 1
@@ -1441,7 +1422,7 @@ notarize() {
 
 i18n() {
     local cmd="$1"
-    if [ "$cmd" == "" ]; then
+    if [ -z "$cmd" ]; then
         logError "No subcommand specified.\n"
         printUsage i18n
         exit 1
@@ -1452,12 +1433,16 @@ i18n() {
     fi
     shift
 
+    checkGitRepository
+
     if [ "$cmd" == "lupdate" ]; then
         if [ ! -d share/translations ]; then
             logError "Command must be called from repository root directory."
             exit 1
         fi
 
+        checkQt5LUpdateExists
+
         logInfo "Updating source translation file..."
         LUPDATE=lupdate-qt5
         if ! command -v $LUPDATE > /dev/null; then
@@ -1469,6 +1454,8 @@ i18n() {
         return 0
     fi
 
+    checkTransifexCommandExists
+
     local branch="$(git branch --show-current 2>&1)"
     local real_branch="$branch"
     if [[ "$branch" =~ ^release/ ]]; then
@@ -1504,8 +1491,8 @@ i18n() {
 #                       parse global command line
 # -----------------------------------------------------------------------
 MODE="$1"
-shift
-if [ "" == "$MODE" ]; then
+shift || true
+if [ -z "$MODE" ]; then
     logError "Missing arguments!\n"
     printUsage
     exit 1