diff --git a/docker-compose.yml b/docker-compose.yml
index a1b6ebb..b56a3c5 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -19,6 +19,7 @@ name: libvmod-cfg-master
 services:
   dev:
     hostname: dev
+    # platform: linux/arm64/v8
     build:
       context: .
       no_cache: true
diff --git a/src/variables.c b/src/variables.c
index 1e457da..cf4f799 100644
--- a/src/variables.c
+++ b/src/variables.c
@@ -129,7 +129,7 @@ static const char *json_hex_chars = "0123456789abcdef";
     do { \
         DUMP_CHAR('"'); \
         for (int i = 0; value[i]; i++) { \
-            if (value[i] > 31 && value[i] != '\"' && value[i] != '\\') { \
+            if (value[i] > 31 && value[i] < 127 && value[i] != '\"' && value[i] != '\\') { \
                 DUMP_CHAR(value[i]); \
             } else { \
                 DUMP_CHAR('\\'); \