diff --git a/.github/workflows/test-lint-deploy.yml b/.github/workflows/test-lint-deploy.yml
index cd5c24c..945b05f 100644
--- a/.github/workflows/test-lint-deploy.yml
+++ b/.github/workflows/test-lint-deploy.yml
@@ -30,7 +30,7 @@ concurrency:
 
 jobs:
   build-deploy:
-    timeout-minutes: 30
+    timeout-minutes: 45
 
     runs-on: ubuntu-22.04
 
@@ -92,8 +92,8 @@ jobs:
           chmod +x mdslw
           sudo mv mdslw /usr/local/bin
         env:
-          MDSLW_VERSION: 0.6.1
-          MDSLW_SHA256: 20814371ec7c1801b995aa2e506a71ea1a3b23a4affa977ca75b02ad3dd5c562
+          MDSLW_VERSION: 0.11.1
+          MDSLW_SHA256: 75a172e9d9a59793a4dbb5adb0e0dd0778171c6aa07188fc0733bb20c6889e1e
           BASE_URL: "https://github.com/razziel89/mdslw/releases/download"
 
       - uses: actions/checkout@v3
diff --git a/Makefile b/Makefile
index bfedf1e..5fa5b24 100644
--- a/Makefile
+++ b/Makefile
@@ -79,7 +79,7 @@ test-bash-version:
 	echo >&2 "INFO: using $$(which bash) @ $$(bash -c 'echo $${BASH_VERSION}')" && \
 	$(MAKE) test TEST_SHELL="$$(which bash)"
 
-SUPPORTED_VERSIONS := 5.2 5.1 5.0 4.4
+SUPPORTED_VERSIONS ?= 5.2 5.1 5.0 4.4
 
 .PHONY: test-bash-versions
 test-bash-versions: build
diff --git a/bin/mock_exe.sh b/bin/mock_exe.sh
index 19266ad..24bb1f8 100755
--- a/bin/mock_exe.sh
+++ b/bin/mock_exe.sh
@@ -140,10 +140,10 @@ output_args_and_stdin() {
   local outdir="$1"
   shift
 
-  # Split arguments by newlines. This will cause problems if there are ever
-  # arguments with newlines, of course. Improvements are welcome.
+  # Split arguments by null bytes.
+  local arg
   for arg in "$@"; do
-    printf -- "%s\n" "${arg-}"
+    printf -- "%s\0" "${arg-}"
   done > "${outdir}/args"
   # If stdin is a terminal, we are called interactively. Don't output our stdin
   # in this case. Only output our stdin if we are not invoked interactively.
@@ -190,7 +190,7 @@ _match_spec() {
   shift
 
   local spec
-  while read -r spec; do
+  while IFS= read -d $'\0' -r spec; do
     local id val
     id="${spec%%:*}"
     val="${spec#*:}"
@@ -265,7 +265,7 @@ find_matching_argspec() {
   shift 3
 
   local env_var var
-  while read -r env_var; do
+  while IFS= read -r env_var; do
 
     if _match_spec "${!env_var}" "$@"; then
       echo "${env_var##MOCK_ARGSPEC_BASE32_}"
diff --git a/lib/command_commands.bash b/lib/command_commands.bash
index e2e0b65..e871c66 100644
--- a/lib/command_commands.bash
+++ b/lib/command_commands.bash
@@ -65,12 +65,12 @@ __shellmock__commands() {
 
   declare -A builtins
   local tmp
-  while read -r tmp; do
+  while IFS= read -r tmp; do
     builtins["${tmp}"]=1
   done < <(compgen -b) && wait $! || return 1
 
   local cmd
-  while read -r tmp; do
+  while IFS= read -r tmp; do
     cmd="${tmp%:*}"
     # Only output if it is neither a currently defined function or a built-in.
     if
diff --git a/lib/main.bash b/lib/main.bash
index e6a1e6b..95bddca 100644
--- a/lib/main.bash
+++ b/lib/main.bash
@@ -23,6 +23,7 @@
 # a tool such as getopt or getopts.
 shellmock() {
   # Handle the user requesting a help text.
+  local arg
   for arg in "$@"; do
     if [[ ${arg} == --help ]]; then
       set -- "help"
diff --git a/lib/mock_management.bash b/lib/mock_management.bash
index 42d6b27..0cea801 100644
--- a/lib/mock_management.bash
+++ b/lib/mock_management.bash
@@ -69,7 +69,7 @@ __shellmock__unmock() {
   # are identified by their argspecs or return codes. Thus, we only remove those
   # env vars.
   local env_var
-  while read -r env_var; do
+  while IFS= read -r env_var; do
     unset "${env_var}"
   done < <(
     local var
@@ -98,7 +98,7 @@ __shellmock_assert_no_duplicate_argspecs() {
 
   declare -A arg_idx_count=()
   declare -a duplicate_arg_indices=()
-  local count
+  local count arg
   for arg in "${args[@]}"; do
     idx=${arg%%:*}
     idx=${idx#regex-}
@@ -145,6 +145,7 @@ __shellmock__config() {
   fi
 
   # Validate input format.
+  local arg
   local args=()
   local has_err=0
   local regex='^(regex-[0-9][0-9]*|regex-any|i|[0-9][0-9]*|any):'
@@ -225,7 +226,7 @@ __shellmock__config() {
 
   # Handle arg specs.
   env_var_val=$(for arg in "${args[@]}"; do
-    echo "${arg}"
+    printf "%s\0" "${arg}"
   done | PATH="${__SHELLMOCK_ORGPATH}" base32 -w0)
   env_var_name="MOCK_ARGSPEC_BASE32_${cmd_b32}_${padded}"
   declare -gx "${env_var_name}=${env_var_val}"
@@ -281,7 +282,7 @@ __shellmock__assert() {
 
     local has_err=0
     local stderr
-    while read -r stderr; do
+    while IFS= read -r stderr; do
       if [[ -s ${stderr} ]]; then
         PATH="${__SHELLMOCK_ORGPATH}" cat >&2 "${stderr}"
         has_err=1
@@ -332,8 +333,14 @@ __shellmock__assert() {
     for argspec in "${expected_argspecs[@]}"; do
       if ! [[ " ${actual_argspecs[*]} " == *"${argspec}"* ]]; then
         has_err=1
-        echo >&2 "SHELLMOCK: cannot find call for mock ${cmd} and argspec:" \
-          "$(PATH="${__SHELLMOCK_ORGPATH}" base32 --decode <<< "${!argspec}")"
+        local msg_args=()
+        readarray -d $'\0' -t msg_args < <(
+          PATH="${__SHELLMOCK_ORGPATH}" base32 --decode <<< "${!argspec}"
+        ) && wait $! || exit 1
+        (
+          IFS=" " && echo >&2 "SHELLMOCK: cannot find call for mock ${cmd}" \
+            "and argspec: ${msg_args[*]}"
+        )
       fi
     done
     if [[ ${has_err} -ne 0 ]]; then
@@ -422,7 +429,7 @@ __shellmock__calls() {
 
     # Extract arguments and stdin. Shell-quote everything for the suggestion.
     local args=()
-    readarray -d $'\n' -t args < "${call_id}/args"
+    readarray -d $'\0' -t args < "${call_id}/args"
     local idx
     for idx in "${!args[@]}"; do
       local arg="${args[${idx}]}"
diff --git a/tests/main.bats b/tests/main.bats
index 7bf5e2e..f6fe89e 100644
--- a/tests/main.bats
+++ b/tests/main.bats
@@ -60,6 +60,15 @@ setup() {
   git checkout
 }
 
+@test "a concrete example with whitespace" {
+  # This concrete example uses the "git" executable with the "checkout" command.
+  # You could mock it like this analogous to the previous test.
+  shellmock new git
+  shellmock config git 0 1:checkout 2:"my branch" 3:main
+  # Git mock can be called with the checkout command.
+  git checkout "my branch" main
+}
+
 @test "we can mock a function" {
   # When calling an identifier, e.g. "git", the shell will give precedence to
   # functions. That is, if there is a function called "git" and an executable in
diff --git a/tests/misc.bats b/tests/misc.bats
index 55be150..2e494ec 100644
--- a/tests/misc.bats
+++ b/tests/misc.bats
@@ -79,6 +79,7 @@ setup() {
 @test "mocking executables with unusual names" {
   for exe in happy😀face exe-with-dash chinese龙dragon "exe with spaces"; do
     (
+      echo >&2 "Testing executable: ${exe@Q}"
       # Make sure the test fails as soon as one command errors out, even though
       # we are in a subshell.
       set -euo pipefail
@@ -91,6 +92,26 @@ setup() {
       "${exe}" arg
       # Make sure assertions work for such mocks.
       shellmock assert expectations "${exe}"
+      echo >&2 "Success for executable: ${exe@Q}"
+    )
+  done
+}
+
+@test "using arguments with (fancy) whitespace" {
+  for arg in "a b" $'a\tb' $'a\nb' 'a b' " " " a "; do
+    (
+      echo >&2 "Testing arg: ${arg@Q}"
+      # Make sure the test fails as soon as one test errors out, even though
+      # we are in a subshell.
+      set -euo pipefail
+      shellmock new exe
+      # Define the mock to return with success.
+      shellmock config exe 0 1:first-arg 2:"${arg}" 3:third-arg
+      # Call the mock.
+      exe first-arg "${arg}" third-arg
+      # Make sure assertions work for such mocks.
+      shellmock assert expectations exe
+      echo >&2 "Success for arg: ${arg@Q}"
     )
   done
 }