diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index bd79692..cfec816 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -47,7 +47,7 @@ jobs:
         php:
           - "8.2"
         icu:
-          - "70.1"
+          - "75.1"
 
     steps:
       - name: "Checkout repository"
@@ -99,7 +99,7 @@ jobs:
         php:
           - "8.3"
         icu:
-          - "73.2"
+          - "75.1"
 
     steps:
       - name: "Checkout repository"
@@ -146,11 +146,7 @@ jobs:
           - "8.2"
           - "8.3"
         icu:
-          - "70.1"
-          - "71.1"
-          - "72.1"
-          - "73.1"
-          - "73.2"
+          - "75.1"
 
     steps:
       - name: "Checkout repository"
diff --git a/config.m4 b/config.m4
index e1c2d0c..925001e 100644
--- a/config.m4
+++ b/config.m4
@@ -33,7 +33,7 @@ PHP_ARG_ENABLE(
 )
 
 if test "$PHP_ECMA_INTL" != "no"; then
-  PKG_CHECK_MODULES([ICU], [icu-uc >= 70.1 icu-i18n icu-io])
+  PKG_CHECK_MODULES([ICU], [icu-uc >= 75.1 icu-i18n icu-io])
 
   PHP_EVAL_INCLINE($ICU_CFLAGS)
   PHP_EVAL_LIBLINE($ICU_LIBS, ECMA_INTL_SHARED_LIBADD)
@@ -88,7 +88,7 @@ if test "$PHP_ECMA_INTL" != "no"; then
   PHP_ADD_BUILD_DIR($ext_builddir/src/php/classes)
 
   PHP_REQUIRE_CXX()
-  PHP_CXX_COMPILE_STDCXX(11, mandatory, PHP_ECMA_INTL_STDCXX)
+  PHP_CXX_COMPILE_STDCXX(17, mandatory, PHP_ECMA_INTL_STDCXX)
 
   EXTRA_CXXFLAGS="$PHP_ECMA_INTL_STDCXX $ICU_CXXFLAGS"
   PHP_SUBST(EXTRA_CXXFLAGS)
diff --git a/tests/criterion/ecma402/category_test.c b/tests/criterion/ecma402/category_test.c
index d0f0f31..bfcd7e6 100644
--- a/tests/criterion/ecma402/category_test.c
+++ b/tests/criterion/ecma402/category_test.c
@@ -13,7 +13,7 @@
 #define CATEGORY_VALUES_TEST(name, category, capacity)                                                                 \
 	Test(TEST_SUITE, supportedValuesFor##name##Category)                                                               \
 	{                                                                                                                  \
-		const char **values = (const char **)malloc(sizeof(const char *) * capacity);                                  \
+		const char **values = (const char **)malloc(sizeof(char *) * capacity);                                        \
 		const int count = ecma402_supportedValuesForCategory(category, values);                                        \
 		cr_expect(values != NULL);                                                                                     \
 		cr_expect(gt(int, count, 0));                                                                                  \
diff --git a/tests/criterion/ecma402/util_test.cpp b/tests/criterion/ecma402/util_test.cpp
index 420acaa..1c772a4 100644
--- a/tests/criterion/ecma402/util_test.cpp
+++ b/tests/criterion/ecma402/util_test.cpp
@@ -551,7 +551,7 @@ ParameterizedTest(struct splitTestTuple *tup, TEST_SUITE, split)
 
 ParameterizedTestParameters(TEST_SUITE, toAsciiLower)
 {
-	struct charTestTuple tests[189];
+	static struct charTestTuple tests[190];
 	int i = 0;
 
 	// For each printable ASCII character...
@@ -570,7 +570,7 @@ ParameterizedTestParameters(TEST_SUITE, toAsciiLower)
 	}
 
 	// For each printable Latin-1 supplement character...
-	for (wchar_t c = 160; c < 255; c++) {
+	for (wchar_t c = 160; c <= 255; c++) {
 		tests[i].test = c;
 		tests[i].expected = c;
 
@@ -588,7 +588,7 @@ ParameterizedTest(struct charTestTuple *tup, TEST_SUITE, toAsciiLower)
 
 ParameterizedTestParameters(TEST_SUITE, toAsciiUpper)
 {
-	struct charTestTuple tests[189];
+	static struct charTestTuple tests[190];
 	int i = 0;
 
 	// For each printable ASCII character...
@@ -607,7 +607,7 @@ ParameterizedTestParameters(TEST_SUITE, toAsciiUpper)
 	}
 
 	// For each printable Latin-1 supplement character...
-	for (wchar_t c = 160; c < 255; c++) {
+	for (wchar_t c = 160; c <= 255; c++) {
 		tests[i].test = c;
 		tests[i].expected = c;