diff --git a/ext/date/php_date.c b/ext/date/php_date.c
index ed89c9d494a6f..a533552621f2a 100644
--- a/ext/date/php_date.c
+++ b/ext/date/php_date.c
@@ -673,7 +673,7 @@ static const char *php_date_short_day_name(timelib_sll y, timelib_sll m, timelib
 /* }}} */
 
 /* {{{ date_format - (gm)date helper */
-static zend_string *date_format(const char *format, size_t format_len, timelib_time *t, bool localtime)
+static zend_string *date_format(const char *format, size_t format_len, const timelib_time *t, bool localtime)
 {
 	smart_str            string = {0};
 	size_t               i;
@@ -845,7 +845,7 @@ static zend_string *date_format(const char *format, size_t format_len, timelib_t
 	return string.s;
 }
 
-PHPAPI zend_string *php_format_date_obj(const char *format, size_t format_len, php_date_obj *date_obj)
+PHPAPI zend_string *php_format_date_obj(const char *format, size_t format_len, const php_date_obj *date_obj)
 {
 	if (!date_obj->time) {
 		return NULL;
@@ -2807,7 +2807,7 @@ PHP_METHOD(DateTimeImmutable, createFromTimestamp)
 }
 /* }}} */
 
-static bool php_date_initialize_from_hash(php_date_obj **dateobj, HashTable *myht)
+static bool php_date_initialize_from_hash(php_date_obj **dateobj, const HashTable *myht)
 {
 	zval             *z_date;
 	zval             *z_timezone_type;
@@ -2948,7 +2948,7 @@ PHP_METHOD(DateTimeImmutable, __serialize)
 }
 /* }}} */
 
-static bool date_time_is_internal_property(zend_string *name)
+static bool date_time_is_internal_property(const zend_string *name)
 {
 	if (
 		zend_string_equals_literal(name, "date") ||
@@ -2960,7 +2960,7 @@ static bool date_time_is_internal_property(zend_string *name)
 	return 0;
 }
 
-static void restore_custom_datetime_properties(zval *object, HashTable *myht)
+static void restore_custom_datetime_properties(zval *object, const HashTable *myht)
 {
 	zend_string      *prop_name;
 	zval             *prop_val;
@@ -2978,15 +2978,13 @@ PHP_METHOD(DateTime, __unserialize)
 {
 	zval             *object = ZEND_THIS;
 	php_date_obj     *dateobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
 	dateobj = Z_PHPDATE_P(object);
-	myht = Z_ARRVAL_P(array);
 
 	if (!php_date_initialize_from_hash(&dateobj, myht)) {
 		zend_throw_error(NULL, "Invalid serialization data for DateTime object");
@@ -3002,15 +3000,13 @@ PHP_METHOD(DateTimeImmutable, __unserialize)
 {
 	zval             *object = ZEND_THIS;
 	php_date_obj     *dateobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
 	dateobj = Z_PHPDATE_P(object);
-	myht = Z_ARRVAL_P(array);
 
 	if (!php_date_initialize_from_hash(&dateobj, myht)) {
 		zend_throw_error(NULL, "Invalid serialization data for DateTimeImmutable object");
@@ -3027,7 +3023,7 @@ static void php_do_date_time_wakeup(INTERNAL_FUNCTION_PARAMETERS, const char *cl
 {
 	zval             *object = ZEND_THIS;
 	php_date_obj     *dateobj;
-	HashTable        *myht;
+	const HashTable  *myht;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -3057,7 +3053,7 @@ PHP_METHOD(DateTimeImmutable, __wakeup)
 /* }}} */
 
 /* Helper function used to add an associative array of warnings and errors to a zval */
-static void zval_from_error_container(zval *z, timelib_error_container *error) /* {{{ */
+static void zval_from_error_container(zval *z, const timelib_error_container *error) /* {{{ */
 {
 	int   i;
 	zval element;
@@ -3498,7 +3494,7 @@ PHP_METHOD(DateTimeImmutable, sub)
 }
 /* }}} */
 
-static void set_timezone_from_timelib_time(php_timezone_obj *tzobj, timelib_time *t)
+static void set_timezone_from_timelib_time(php_timezone_obj *tzobj, const timelib_time *t)
 {
 	/* Free abbreviation if already set */
 	if (tzobj->initialized && tzobj->type == TIMELIB_ZONETYPE_ABBR) {
@@ -4057,7 +4053,7 @@ PHP_METHOD(DateTimeZone, __construct)
 }
 /* }}} */
 
-static bool php_date_timezone_initialize_from_hash(zval **return_value, php_timezone_obj **tzobj, HashTable *myht) /* {{{ */
+static bool php_date_timezone_initialize_from_hash(zval **return_value, php_timezone_obj **tzobj, const HashTable *myht) /* {{{ */
 {
 	zval            *z_timezone_type;
 
@@ -4087,15 +4083,12 @@ static bool php_date_timezone_initialize_from_hash(zval **return_value, php_time
 PHP_METHOD(DateTimeZone, __set_state)
 {
 	php_timezone_obj *tzobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
-	myht = Z_ARRVAL_P(array);
-
 	php_date_instantiate(date_ce_timezone, return_value);
 	tzobj = Z_PHPTIMEZONE_P(return_value);
 	if (!php_date_timezone_initialize_from_hash(&return_value, &tzobj, myht)) {
@@ -4110,7 +4103,7 @@ PHP_METHOD(DateTimeZone, __wakeup)
 {
 	zval             *object = ZEND_THIS;
 	php_timezone_obj *tzobj;
-	HashTable        *myht;
+	const HashTable  *myht;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -4145,7 +4138,7 @@ PHP_METHOD(DateTimeZone, __serialize)
 }
 /* }}} */
 
-static bool date_timezone_is_internal_property(zend_string *name)
+static bool date_timezone_is_internal_property(const zend_string *name)
 {
 	if (
 		zend_string_equals_literal(name, "timezone_type") ||
@@ -4156,7 +4149,7 @@ static bool date_timezone_is_internal_property(zend_string *name)
 	return 0;
 }
 
-static void restore_custom_datetimezone_properties(zval *object, HashTable *myht)
+static void restore_custom_datetimezone_properties(zval *object, const HashTable *myht)
 {
 	zend_string      *prop_name;
 	zval             *prop_val;
@@ -4174,15 +4167,13 @@ PHP_METHOD(DateTimeZone, __unserialize)
 {
 	zval             *object = ZEND_THIS;
 	php_timezone_obj *tzobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
 	tzobj = Z_PHPTIMEZONE_P(object);
-	myht = Z_ARRVAL_P(array);
 
 	if (!php_date_timezone_initialize_from_hash(&object, &tzobj, myht)) {
 		zend_throw_error(NULL, "Invalid serialization data for DateTimeZone object");
@@ -4422,7 +4413,7 @@ PHP_FUNCTION(timezone_location_get)
 }
 /* }}} */
 
-static bool date_interval_initialize(timelib_rel_time **rt, /*const*/ char *format, size_t format_length) /* {{{ */
+static bool date_interval_initialize(timelib_rel_time **rt, const char *format, size_t format_length) /* {{{ */
 {
 	timelib_time     *b = NULL, *e = NULL;
 	timelib_rel_time *p = NULL;
@@ -4607,10 +4598,10 @@ PHP_METHOD(DateInterval, __construct)
 }
 /* }}} */
 
-static void php_date_interval_initialize_from_hash(zval **return_value, php_interval_obj **intobj, HashTable *myht) /* {{{ */
+static void php_date_interval_initialize_from_hash(zval **return_value, php_interval_obj **intobj, const HashTable *myht) /* {{{ */
 {
 	/* If we have a date_string, use that instead */
-	zval *date_str = zend_hash_str_find(myht, "date_string", strlen("date_string"));
+	const zval *date_str = zend_hash_str_find(myht, "date_string", strlen("date_string"));
 	if (date_str && Z_TYPE_P(date_str) == IS_STRING) {
 		timelib_time   *time;
 		timelib_error_container *err = NULL;
@@ -4708,7 +4699,7 @@ static void php_date_interval_initialize_from_hash(zval **return_value, php_inte
 	PHP_DATE_INTERVAL_READ_PROPERTY("i", i, timelib_sll, -1)
 	PHP_DATE_INTERVAL_READ_PROPERTY("s", s, timelib_sll, -1)
 	{
-		zval *z_arg = zend_hash_str_find(myht, "f", sizeof("f") - 1);
+		const zval *z_arg = zend_hash_str_find(myht, "f", sizeof("f") - 1);
 		if (z_arg) {
 			(*intobj)->diff->us = zend_dval_to_lval(zval_get_double(z_arg) * 1000000.0);
 		}
@@ -4723,7 +4714,7 @@ static void php_date_interval_initialize_from_hash(zval **return_value, php_inte
 	PHP_DATE_INTERVAL_READ_PROPERTY("have_weekday_relative", have_weekday_relative, unsigned int, 0);
 	PHP_DATE_INTERVAL_READ_PROPERTY("have_special_relative", have_special_relative, unsigned int, 0);
 	{
-		zval *z_arg = zend_hash_str_find(myht, "civil_or_wall", sizeof("civil_or_wall") - 1);
+		const zval *z_arg = zend_hash_str_find(myht, "civil_or_wall", sizeof("civil_or_wall") - 1);
 		(*intobj)->civil_or_wall = PHP_DATE_CIVIL;
 		if (z_arg) {
 			zend_long val = zval_get_long(z_arg);
@@ -4738,15 +4729,12 @@ static void php_date_interval_initialize_from_hash(zval **return_value, php_inte
 PHP_METHOD(DateInterval, __set_state)
 {
 	php_interval_obj *intobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
-	myht = Z_ARRVAL_P(array);
-
 	php_date_instantiate(date_ce_interval, return_value);
 	intobj = Z_PHPINTERVAL_P(return_value);
 	php_date_interval_initialize_from_hash(&return_value, &intobj, myht);
@@ -4773,7 +4761,7 @@ PHP_METHOD(DateInterval, __serialize)
 }
 /* }}} */
 
-static bool date_interval_is_internal_property(zend_string *name)
+static bool date_interval_is_internal_property(const zend_string *name)
 {
 	if (
 		zend_string_equals_literal(name, "date_string") ||
@@ -4793,7 +4781,7 @@ static bool date_interval_is_internal_property(zend_string *name)
 	return 0;
 }
 
-static void restore_custom_dateinterval_properties(zval *object, HashTable *myht)
+static void restore_custom_dateinterval_properties(zval *object, const HashTable *myht)
 {
 	zend_string      *prop_name;
 	zval             *prop_val;
@@ -4812,15 +4800,13 @@ PHP_METHOD(DateInterval, __unserialize)
 {
 	zval             *object = ZEND_THIS;
 	php_interval_obj *intervalobj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
 	intervalobj = Z_PHPINTERVAL_P(object);
-	myht = Z_ARRVAL_P(array);
 
 	php_date_interval_initialize_from_hash(&object, &intervalobj, myht);
 	restore_custom_dateinterval_properties(object, myht);
@@ -4832,7 +4818,7 @@ PHP_METHOD(DateInterval, __wakeup)
 {
 	zval             *object = ZEND_THIS;
 	php_interval_obj *intobj;
-	HashTable        *myht;
+	const HashTable  *myht;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -4924,7 +4910,7 @@ PHP_METHOD(DateInterval, createFromDateString)
 /* }}} */
 
 /* {{{ date_interval_format -  */
-static zend_string *date_interval_format(char *format, size_t format_len, timelib_rel_time *t)
+static zend_string *date_interval_format(const char *format, size_t format_len, timelib_rel_time *t)
 {
 	smart_str            string = {0};
 	size_t               i;
@@ -4998,7 +4984,7 @@ PHP_FUNCTION(date_interval_format)
 {
 	zval             *object;
 	php_interval_obj *diobj;
-	char             *format;
+	const char       *format;
 	size_t            format_len;
 
 	if (zend_parse_method_parameters(ZEND_NUM_ARGS(), getThis(), "Os", &object, date_ce_interval, &format, &format_len) == FAILURE) {
@@ -5011,7 +4997,7 @@ PHP_FUNCTION(date_interval_format)
 }
 /* }}} */
 
-static bool date_period_initialize(timelib_time **st, timelib_time **et, timelib_rel_time **d, zend_long *recurrences, /*const*/ char *format, size_t format_length) /* {{{ */
+static bool date_period_initialize(timelib_time **st, timelib_time **et, timelib_rel_time **d, zend_long *recurrences, const char *format, size_t format_length) /* {{{ */
 {
 	timelib_time     *b = NULL, *e = NULL;
 	timelib_rel_time *p = NULL;
@@ -5044,7 +5030,7 @@ static bool date_period_initialize(timelib_time **st, timelib_time **et, timelib
 	return retval;
 } /* }}} */
 
-static bool date_period_init_iso8601_string(php_period_obj *dpobj, zend_class_entry* base_ce, char *isostr, size_t isostr_len, zend_long options, zend_long *recurrences)
+static bool date_period_init_iso8601_string(php_period_obj *dpobj, zend_class_entry* base_ce, const char *isostr, size_t isostr_len, zend_long *recurrences)
 {
 	if (!date_period_initialize(&(dpobj->start), &(dpobj->end), &(dpobj->interval), recurrences, isostr, isostr_len)) {
 		return false;
@@ -5130,7 +5116,7 @@ PHP_METHOD(DatePeriod, createFromISO8601String)
 
 	dpobj->current = NULL;
 
-	if (!date_period_init_iso8601_string(dpobj, date_ce_immutable, isostr, isostr_len, options, &recurrences)) {
+	if (!date_period_init_iso8601_string(dpobj, date_ce_immutable, isostr, isostr_len, &recurrences)) {
 		RETURN_THROWS();
 	}
 
@@ -5169,7 +5155,7 @@ PHP_METHOD(DatePeriod, __construct)
 			RETURN_THROWS();
 		}
 
-		if (!date_period_init_iso8601_string(dpobj, date_ce_date, isostr, isostr_len, options, &recurrences)) {
+		if (!date_period_init_iso8601_string(dpobj, date_ce_date, isostr, isostr_len, &recurrences)) {
 			RETURN_THROWS();
 		}
 	} else {
@@ -5305,7 +5291,7 @@ PHP_METHOD(DatePeriod, getIterator)
 	zend_create_internal_iterator_zval(return_value, ZEND_THIS);
 }
 
-static int check_id_allowed(char *id, zend_long what) /* {{{ */
+static bool check_id_allowed(const char *id, zend_long what) /* {{{ */
 {
 	if ((what & PHP_DATE_TIMEZONE_GROUP_AFRICA)     && strncasecmp(id, "Africa/",      7) == 0) return 1;
 	if ((what & PHP_DATE_TIMEZONE_GROUP_AMERICA)    && strncasecmp(id, "America/",     8) == 0) return 1;
@@ -5711,7 +5697,7 @@ static void date_period_object_to_hash(php_period_obj *period_obj, HashTable *pr
 	zend_hash_str_update(props, "include_end_date", sizeof("include_end_date")-1, &zv);
 }
 
-static bool php_date_period_initialize_from_hash(php_period_obj *period_obj, HashTable *myht) /* {{{ */
+static bool php_date_period_initialize_from_hash(php_period_obj *period_obj, const HashTable *myht) /* {{{ */
 {
 	zval *ht_entry;
 
@@ -5835,15 +5821,12 @@ static bool php_date_period_initialize_from_hash(php_period_obj *period_obj, Has
 PHP_METHOD(DatePeriod, __set_state)
 {
 	php_period_obj   *period_obj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
-	myht = Z_ARRVAL_P(array);
-
 	object_init_ex(return_value, date_ce_period);
 	period_obj = Z_PHPPERIOD_P(return_value);
 	if (!php_date_period_initialize_from_hash(period_obj, myht)) {
@@ -5877,7 +5860,7 @@ PHP_METHOD(DatePeriod, __serialize)
  *  Common for date_period_read_property(), date_period_write_property(), and
  *  restore_custom_dateperiod_properties functions
  */
-static bool date_period_is_internal_property(zend_string *name)
+static bool date_period_is_internal_property(const zend_string *name)
 {
 	if (
 		zend_string_equals_literal(name, "start") ||
@@ -5894,7 +5877,7 @@ static bool date_period_is_internal_property(zend_string *name)
 }
 /* }}} */
 
-static void restore_custom_dateperiod_properties(zval *object, HashTable *myht)
+static void restore_custom_dateperiod_properties(zval *object, const HashTable *myht)
 {
 	zend_string      *prop_name;
 	zval             *prop_val;
@@ -5912,15 +5895,13 @@ PHP_METHOD(DatePeriod, __unserialize)
 {
 	zval             *object = ZEND_THIS;
 	php_period_obj   *period_obj;
-	zval             *array;
 	HashTable        *myht;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_ARRAY(array)
+		Z_PARAM_ARRAY_HT(myht)
 	ZEND_PARSE_PARAMETERS_END();
 
 	period_obj = Z_PHPPERIOD_P(object);
-	myht = Z_ARRVAL_P(array);
 
 	if (!php_date_period_initialize_from_hash(period_obj, myht)) {
 		zend_throw_error(NULL, "Invalid serialization data for DatePeriod object");
@@ -5935,7 +5916,7 @@ PHP_METHOD(DatePeriod, __wakeup)
 {
 	zval             *object = ZEND_THIS;
 	php_period_obj   *period_obj;
-	HashTable        *myht;
+	const HashTable  *myht;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
diff --git a/ext/date/php_date.h b/ext/date/php_date.h
index f1b7c892001a9..f5f43bc7dfb0f 100644
--- a/ext/date/php_date.h
+++ b/ext/date/php_date.h
@@ -89,9 +89,9 @@ static inline php_timezone_obj *php_timezone_obj_from_obj(zend_object *obj) {
 struct _php_interval_obj {
 	timelib_rel_time *diff;
 	int               civil_or_wall;
+	bool              initialized;
 	bool              from_string;
 	zend_string      *date_string;
-	bool              initialized;
 	zend_object       std;
 };
 
@@ -140,7 +140,7 @@ PHPAPI int php_idate(char format, time_t ts, bool localtime);
 
 PHPAPI void php_strftime(INTERNAL_FUNCTION_PARAMETERS, bool gm);
 PHPAPI zend_string *php_format_date(const char *format, size_t format_len, time_t ts, bool localtime);
-PHPAPI zend_string *php_format_date_obj(const char *format, size_t format_len, php_date_obj *date_obj);
+PHPAPI zend_string *php_format_date_obj(const char *format, size_t format_len, const php_date_obj *date_obj);
 
 /* Mechanism to set new TZ database */
 PHPAPI void php_date_set_tzdb(timelib_tzdb *tzdb);