diff --git a/modules/arch/win32/mod_isapi.c b/modules/arch/win32/mod_isapi.c
index 2265dd8297..0825c05faf 100644
--- a/modules/arch/win32/mod_isapi.c
+++ b/modules/arch/win32/mod_isapi.c
@@ -567,7 +567,7 @@ BOOL WINAPI GetServerVariable (HCONN hConn, LPSTR lpszVariableName,
         /* lf delimited, colon split, comma seperated and 
          * null terminated list of HTTP_ vars 
          */
-        char **env = (char**) apr_table_elts(r->subprocess_env)->elts;
+        const char * const *env = (const char* const *) apr_table_elts(r->subprocess_env)->elts;
         int nelts = 2 * apr_table_elts(r->subprocess_env)->nelts;
         int i;
 
@@ -601,7 +601,7 @@ BOOL WINAPI GetServerVariable (HCONN hConn, LPSTR lpszVariableName,
         /* lf delimited, colon split, comma seperated and 
          * null terminated list of the raw request header
          */
-        char **raw = (char**) apr_table_elts(r->headers_in)->elts;
+        const char * const *raw = (const char* const *) apr_table_elts(r->headers_in)->elts;
         int nelts = 2 * apr_table_elts(r->headers_in)->nelts;
         int i;
 
diff --git a/modules/dav/main/mod_dav.c b/modules/dav/main/mod_dav.c
index 14388ae4c1..8272daf3e9 100644
--- a/modules/dav/main/mod_dav.c
+++ b/modules/dav/main/mod_dav.c
@@ -1216,8 +1216,8 @@ static dav_error *dav_gen_supported_methods(request_rec *r,
                                             const apr_table_t *methods,
                                             ap_text_header *body)
 {
-    apr_array_header_t *arr;
-    apr_table_entry_t *elts;
+    const apr_array_header_t *arr;
+    const apr_table_entry_t *elts;
     ap_xml_elem *child;
     ap_xml_attr *attr;
     char *s;
@@ -1228,7 +1228,7 @@ static dav_error *dav_gen_supported_methods(request_rec *r,
     if (elem->first_child == NULL) {
         /* show all supported methods */
         arr = apr_table_elts(methods);
-        elts = (apr_table_entry_t *) arr->elts;
+        elts = (const apr_table_entry_t *) arr->elts;
 
         for (i = 0; i < arr->nelts; ++i) {
             if (elts[i].key == NULL)
@@ -1459,8 +1459,8 @@ static int dav_method_options(request_rec *r)
     const char *dav_level;
     char *allow;
     char *s;
-    apr_array_header_t *arr;
-    apr_table_entry_t *elts;
+    const apr_array_header_t *arr;
+    const apr_table_entry_t *elts;
     apr_table_t *methods = apr_table_make(r->pool, 12);
     ap_text_header vsn_options = { 0 };
     ap_text_header body = { 0 };
@@ -1641,7 +1641,7 @@ static int dav_method_options(request_rec *r)
 
     /* Generate the Allow header */
     arr = apr_table_elts(methods);
-    elts = (apr_table_entry_t *) arr->elts;
+    elts = (const apr_table_entry_t *) arr->elts;
     text_size = 0;
 
     /* first, compute total length */
diff --git a/modules/filters/mod_include.c b/modules/filters/mod_include.c
index 9768022a68..051671d273 100644
--- a/modules/filters/mod_include.c
+++ b/modules/filters/mod_include.c
@@ -2609,8 +2609,8 @@ static int handle_printenv(include_ctx_t *ctx, apr_bucket_brigade **bb,
     if (ctx->flags & FLAG_PRINTING) {
         ap_ssi_get_tag_and_value(ctx, &tag, &tag_val, 1);
         if ((tag == NULL) && (tag_val == NULL)) {
-            apr_array_header_t *arr = apr_table_elts(r->subprocess_env);
-            apr_table_entry_t *elts = (apr_table_entry_t *)arr->elts;
+            const apr_array_header_t *arr = apr_table_elts(r->subprocess_env);
+            const apr_table_entry_t *elts = (const apr_table_entry_t *)arr->elts;
             int i;
             const char *key_text, *val_text;
             apr_size_t   k_len, v_len, t_wrt;
diff --git a/modules/generators/mod_cgi.c b/modules/generators/mod_cgi.c
index 633d9458ee..f5344187da 100644
--- a/modules/generators/mod_cgi.c
+++ b/modules/generators/mod_cgi.c
@@ -257,8 +257,8 @@ static int log_script(request_rec *r, cgi_server_conf * conf, int ret,
 		  char *dbuf, const char *sbuf, apr_file_t *script_in, 
                   apr_file_t *script_err)
 {
-    apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in);
-    apr_table_entry_t *hdrs = (apr_table_entry_t *) hdrs_arr->elts;
+    const apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in);
+    const apr_table_entry_t *hdrs = (const apr_table_entry_t *) hdrs_arr->elts;
     char argsbuffer[HUGE_STRING_LEN];
     apr_file_t *f = NULL;
     int i;
@@ -300,7 +300,7 @@ static int log_script(request_rec *r, cgi_server_conf * conf, int ret,
 
     apr_file_puts("%response\n", f);
     hdrs_arr = apr_table_elts(r->err_headers_out);
-    hdrs = (apr_table_entry_t *) hdrs_arr->elts;
+    hdrs = (const apr_table_entry_t *) hdrs_arr->elts;
 
     for (i = 0; i < hdrs_arr->nelts; ++i) {
 	if (!hdrs[i].key)
diff --git a/modules/generators/mod_cgid.c b/modules/generators/mod_cgid.c
index 91bfd76bff..f5e34a81f4 100644
--- a/modules/generators/mod_cgid.c
+++ b/modules/generators/mod_cgid.c
@@ -749,8 +749,8 @@ static int log_scripterror(request_rec *r, cgid_server_conf * conf, int ret,
 static int log_script(request_rec *r, cgid_server_conf * conf, int ret, 
                   char *dbuf, const char *sbuf, apr_file_t *script_in, apr_file_t *script_err) 
 { 
-    apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in); 
-    apr_table_entry_t *hdrs = (apr_table_entry_t *) hdrs_arr->elts; 
+    const apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in); 
+    const apr_table_entry_t *hdrs = (apr_table_entry_t *) hdrs_arr->elts; 
     char argsbuffer[HUGE_STRING_LEN]; 
     apr_file_t *f = NULL; 
     int i; 
@@ -795,7 +795,7 @@ static int log_script(request_rec *r, cgid_server_conf * conf, int ret,
 
     apr_file_puts("%response\n", f); 
     hdrs_arr = apr_table_elts(r->err_headers_out); 
-    hdrs = (apr_table_entry_t *) hdrs_arr->elts; 
+    hdrs = (const apr_table_entry_t *) hdrs_arr->elts; 
 
     for (i = 0; i < hdrs_arr->nelts; ++i) { 
         if (!hdrs[i].key) 
diff --git a/modules/http/http_request.c b/modules/http/http_request.c
index b95fb04d7c..e35ec058ba 100644
--- a/modules/http/http_request.c
+++ b/modules/http/http_request.c
@@ -310,8 +310,8 @@ void ap_process_request(request_rec *r)
 
 static apr_table_t *rename_original_env(apr_pool_t *p, apr_table_t *t)
 {
-    apr_array_header_t *env_arr = apr_table_elts(t);
-    apr_table_entry_t *elts = (apr_table_entry_t *) env_arr->elts;
+    const apr_array_header_t *env_arr = apr_table_elts(t);
+    const apr_table_entry_t *elts = (const apr_table_entry_t *) env_arr->elts;
     apr_table_t *new = apr_table_make(p, env_arr->nalloc);
     int i;
 
diff --git a/modules/mappers/mod_rewrite.c b/modules/mappers/mod_rewrite.c
index 556c73f5bc..7cc8c9a6b5 100644
--- a/modules/mappers/mod_rewrite.c
+++ b/modules/mappers/mod_rewrite.c
@@ -3627,12 +3627,12 @@ static char *lookup_variable(request_rec *r, char *var)
 
 static char *lookup_header(request_rec *r, const char *name)
 {
-    apr_array_header_t *hdrs_arr;
-    apr_table_entry_t *hdrs;
+    const apr_array_header_t *hdrs_arr;
+    const apr_table_entry_t *hdrs;
     int i;
 
     hdrs_arr = apr_table_elts(r->headers_in);
-    hdrs = (apr_table_entry_t *)hdrs_arr->elts;
+    hdrs = (const apr_table_entry_t *)hdrs_arr->elts;
     for (i = 0; i < hdrs_arr->nelts; ++i) {
         if (hdrs[i].key == NULL) {
             continue;
diff --git a/modules/metadata/mod_env.c b/modules/metadata/mod_env.c
index 5a4a745420..eb24f6cf25 100644
--- a/modules/metadata/mod_env.c
+++ b/modules/metadata/mod_env.c
@@ -92,8 +92,8 @@ static void *merge_env_dir_configs(apr_pool_t *p, void *basev, void *addv)
     env_dir_config_rec *add = addv;
     env_dir_config_rec *res = apr_palloc(p, sizeof(*res));
 
-    apr_table_entry_t *elts;
-    apr_array_header_t *arr;
+    const apr_table_entry_t *elts;
+    const apr_array_header_t *arr;
 
     int i;
 
@@ -111,14 +111,14 @@ static void *merge_env_dir_configs(apr_pool_t *p, void *basev, void *addv)
     res->unsetenv = NULL;
 
     arr = apr_table_elts(add->unsetenv);
-    elts = (apr_table_entry_t *)arr->elts;
+    elts = (const apr_table_entry_t *)arr->elts;
 
     for (i = 0; i < arr->nelts; ++i) {
         apr_table_unset(res->vars, elts[i].key);
     }
 
     arr = apr_table_elts(add->vars);
-    elts = (apr_table_entry_t *)arr->elts;
+    elts = (const apr_table_entry_t *)arr->elts;
 
     for (i = 0; i < arr->nelts; ++i) {
         apr_table_setn(res->vars, elts[i].key, elts[i].val);
diff --git a/modules/metadata/mod_setenvif.c b/modules/metadata/mod_setenvif.c
index 761fcc75ec..6b3b0f27c1 100644
--- a/modules/metadata/mod_setenvif.c
+++ b/modules/metadata/mod_setenvif.c
@@ -406,7 +406,7 @@ static int match_headers(request_rec *r)
 {
     sei_cfg_rec *sconf;
     sei_entry *entries;
-    apr_table_entry_t *elts;
+    const apr_table_entry_t *elts;
     const char *val;
     int i, j;
     char *last_name;
@@ -459,8 +459,8 @@ static int match_headers(request_rec *r)
                      * the headers_in until we find a match or run out of
                      * headers.
                      */
-                    apr_array_header_t *arr = apr_table_elts(r->headers_in);
-                    elts = (apr_table_entry_t *) arr->elts;
+                    const apr_array_header_t *arr = apr_table_elts(r->headers_in);
+                    elts = (const apr_table_entry_t *) arr->elts;
                     val = NULL;
                     for (j = 0; j < arr->nelts; ++j) {
                         if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL, 0)) { 
@@ -489,8 +489,8 @@ static int match_headers(request_rec *r)
         }
 
         if (!ap_regexec(b->preg, val, 0, NULL, 0)) {
-	    apr_array_header_t *arr = apr_table_elts(b->features);
-            elts = (apr_table_entry_t *) arr->elts;
+	    const apr_array_header_t *arr = apr_table_elts(b->features);
+            elts = (const apr_table_entry_t *) arr->elts;
 
             for (j = 0; j < arr->nelts; ++j) {
                 if (!strcmp(elts[j].val, "!")) {
diff --git a/modules/proxy/proxy_http.c b/modules/proxy/proxy_http.c
index cda1263ece..cc67421d35 100644
--- a/modules/proxy/proxy_http.c
+++ b/modules/proxy/proxy_http.c
@@ -448,8 +448,8 @@ apr_status_t ap_proxy_http_request(apr_pool_t *p, request_rec *r,
     char buffer[HUGE_STRING_LEN];
     char *buf;
     apr_bucket *e;
-    apr_array_header_t *headers_in_array;
-    apr_table_entry_t *headers_in;
+    const apr_array_header_t *headers_in_array;
+    const apr_table_entry_t *headers_in;
     int counter;
     /*
      * Send the HTTP/1.1 request to the remote server
@@ -551,7 +551,7 @@ apr_status_t ap_proxy_http_request(apr_pool_t *p, request_rec *r,
 
     /* send request headers */
     headers_in_array = apr_table_elts(r->headers_in);
-    headers_in = (apr_table_entry_t *) headers_in_array->elts;
+    headers_in = (const apr_table_entry_t *) headers_in_array->elts;
     for (counter = 0; counter < headers_in_array->nelts; counter++) {
         if (headers_in[counter].key == NULL || headers_in[counter].val == NULL
 
diff --git a/server/util_script.c b/server/util_script.c
index 0f3733bea4..e311d7f5cb 100644
--- a/server/util_script.c
+++ b/server/util_script.c
@@ -122,8 +122,8 @@ static char *http2env(apr_pool_t *a, const char *w)
 
 AP_DECLARE(char **) ap_create_environment(apr_pool_t *p, apr_table_t *t)
 {
-    apr_array_header_t *env_arr = apr_table_elts(t);
-    apr_table_entry_t *elts = (apr_table_entry_t *) env_arr->elts;
+    const apr_array_header_t *env_arr = apr_table_elts(t);
+    const apr_table_entry_t *elts = (const apr_table_entry_t *) env_arr->elts;
     char **env = (char **) apr_palloc(p, (env_arr->nelts + 2) * sizeof(char *));
     int i, j;
     char *tz;
@@ -169,8 +169,8 @@ AP_DECLARE(void) ap_add_common_vars(request_rec *r)
     char *env_temp;
 #endif
     const char *host;
-    apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in);
-    apr_table_entry_t *hdrs = (apr_table_entry_t *) hdrs_arr->elts;
+    const apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in);
+    const apr_table_entry_t *hdrs = (const apr_table_entry_t *) hdrs_arr->elts;
     int i;
     apr_port_t rport;
     apr_sockaddr_t *remotesa;