diff --git a/extras/test/40_regression.sh b/extras/test/40_regression.sh
index c7096c1..5272288 100644
--- a/extras/test/40_regression.sh
+++ b/extras/test/40_regression.sh
@@ -3,10 +3,11 @@
 export test_description="Tomb regression tests"
 
 source ./setup
+autoload -U is-at-least
 
 TOMB_VERSION=("2.3" "2.2" "2.0.1" "2.1")
 zshversion=$(zsh --version | awk 'NR==1 {print $2}')
-[[ $zshversion =~ "5.3" ]] && TOMB_VERSION=("2.3")
+{ is-at-least "5.3" $zshversion } && TOMB_VERSION=("2.3")
 
 for version in "${TOMB_VERSION[@]}"; do
     URL="https://files.dyne.org/tomb/old-releases/Tomb-$version.tar.gz"
diff --git a/tomb b/tomb
index 4981585..edb3a5a 100755
--- a/tomb
+++ b/tomb
@@ -1002,7 +1002,7 @@ gpg_decrypt() {
         gpgpopt=(--yes)
         
         # GPG option '--try-secret-key' exist since GPG 2.1
-        { option_is_set -R } && [[ $gpgver =~ "2.1." ]] && {
+        { option_is_set -R } && { autoload -U is-at-least && is-at-least "2.1" $gpgver } && {
             typeset -a recipients
             recipients=(${(s:,:)$(option_value -R)})
             { is_valid_recipients $recipients } || {