diff --git a/README.md b/README.md
index 1ea338a6..d529a14a 100644
--- a/README.md
+++ b/README.md
@@ -314,4 +314,7 @@ This method of installation won't make anything slower or otherwise sub-par.
 
 ### What is the minimum supported zsh version?
 
-Anything below 5.2 definitely won't work. 5.4 definitely will.
+ZSH 5.1 or newer should work.
+
+However, there are too many version, OS, platform, terminal and option configurations to test. If
+Powerlevel10k doesn't work for you, please open an issue.
diff --git a/functions/icons.zsh b/functions/icons.zsh
index ca7b2b0a..d1cccffd 100755
--- a/functions/icons.zsh
+++ b/functions/icons.zsh
@@ -550,8 +550,8 @@ function _p9k_init_icons() {
 function print_icon() {
   local icon_name=$1
   local var_name=POWERLEVEL9K_${icon_name}
-  if [[ -v "$var_name" ]]; then
-    echo -n "${(P)ICON_USER_VARIABLE}"
+  if [[ -n "${(tP)var_name}" ]]; then
+    echo -n "${(P)var_name}"
   else
     echo -n "${icons[$icon_name]}"
   fi
diff --git a/functions/utilities.zsh b/functions/utilities.zsh
index 7a322e57..9821b287 100755
--- a/functions/utilities.zsh
+++ b/functions/utilities.zsh
@@ -22,7 +22,7 @@ function set_default() {
 
   local varname=$1
   shift
-  if [[ -v $varname ]]; then
+  if [[ -n ${(tP)varname} ]]; then
     typeset $flags $varname
   elif [[ "$flags" == *[aA]* ]]; then
     eval "typeset ${(@q)flags} ${(q)varname}=(${(qq)@})"
diff --git a/powerlevel9k.zsh-theme b/powerlevel9k.zsh-theme
index 01a832af..4b3af9ab 100755
--- a/powerlevel9k.zsh-theme
+++ b/powerlevel9k.zsh-theme
@@ -26,9 +26,9 @@ if test -z "${ZSH_VERSION}"; then
   exit 1
 fi
 
-if ! autoload -U is-at-least || ! is-at-least 5.2; then
+if ! autoload -U is-at-least || ! is-at-least 5.1; then
   () {
-    >&2 echo -E "You are using ZSH version $ZSH_VERSION. The minimum required version for Powerlevel10k is 5.2."
+    >&2 echo -E "You are using ZSH version $ZSH_VERSION. The minimum required version for Powerlevel10k is 5.1."
     >&2 echo -E "Type 'echo \$ZSH_VERSION' to see your current zsh version."
     local def=${SHELL:c:A}
     local cur=${${ZSH_ARGZERO#-}:c:A}
@@ -37,7 +37,7 @@ if ! autoload -U is-at-least || ! is-at-least 5.2; then
       >&2 echo -E "The shell you are currently running is likely $cur."
     fi
     local other=${${:-zsh}:c}
-    if [[ -n $other ]] && $other -c 'autoload -U is-at-least && is-at-least 5.2' &>/dev/null; then
+    if [[ -n $other ]] && $other -c 'autoload -U is-at-least && is-at-least 5.1' &>/dev/null; then
       local other_v=$($other -c 'echo -E $ZSH_VERSION' 2>/dev/null)
       if [[ -n $other_v && $other_v != $ZSH_VERSION ]]; then
         >&2 echo -E "You have $other with version $other_v but this is not what you are using."
@@ -55,7 +55,7 @@ if ! autoload -U is-at-least || ! is-at-least 5.2; then
   return 1
 fi
 
-if [[ -v _P9K_SOURCED ]]; then
+if (( $+_P9K_SOURCED )); then
   prompt_powerlevel9k_setup "$@"
   return
 fi
@@ -1680,7 +1680,7 @@ function _p9k_vcs_style() {
 }
 
 function _p9k_vcs_render() {
-  if [[ -v _P9K_NEXT_VCS_DIR ]]; then
+  if (( $+_P9K_NEXT_VCS_DIR )); then
     local -a msg
     local dir=${${GIT_DIR:a}:-$PWD}
     while true; do
@@ -1865,7 +1865,7 @@ function _p9k_vcs_resume() {
 function _p9k_vcs_gitstatus() {
   [[ $POWERLEVEL9K_DISABLE_GITSTATUS == true ]] && return 1
   if [[ $_P9K_REFRESH_REASON == precmd ]]; then
-    if [[ -v _P9K_NEXT_VCS_DIR ]]; then
+    if (( $+_P9K_NEXT_VCS_DIR )); then
       typeset -gH _P9K_NEXT_VCS_DIR=${${GIT_DIR:a}:-$PWD}
     else
       local dir=${${GIT_DIR:a}:-$PWD}