diff --git a/doc/tutorial.md b/doc/tutorial.md
index d794413..3221bc3 100644
--- a/doc/tutorial.md
+++ b/doc/tutorial.md
@@ -113,6 +113,8 @@ int main() {
 }
 ```
 
+@remark The library also supports working with Unicode C++ strings such as **UTF-8**, **UTF-16**, **UTF-32** and **wide-char** (`char8_t`, `char16_t`, `char32_t` and `wchar_t`). For strings with a base type of `char`, it is assumed that the input string consists of an **ASCII** character sequence and is not encoded with any encoding. If your application uses the Unicode encoding **UTF-8** for incoming strings with a base type of `char`, you can define the macro `IPADDRESS_CHAR_IS_UTF8`. In this case, all incoming strings with a base type of `char` will be interpreted as **UTF-8** encoding. Despite the support for Unicode, it's important to note that for successful parsing of IP addresses, the incoming string must contain valid symbols for IP addresses.
+
 ### From uint/To uint
 
 Below is code demonstrating how to create IP addresses from unsigned integers and convert them back to unsigned integers.
@@ -550,6 +552,8 @@ int main() {
 }
 ```
 
+@remark By default, the use of whitespace characters in the scope id is not permitted. If a whitespace character is found in the incoming string within the scope id (for example, `fe80::1ff:fe23:4567:890a%et h2`), an error with the code `error_code::invalid_scope_id` will be generated. However, if for some reason you need to parse and save spaces in the scope id, you can define the macro `IPADDRESS_SCOPE_ID_SUPPORT_SPACES`.
+
 ## Std overrides
 
 @note If, for some reason, you don't want the library to overload standard functions, you can define `IPADDRESS_NO_OVERLOAD_STD` during compilation.
diff --git a/include/ipaddress/base-v6.hpp b/include/ipaddress/base-v6.hpp
index 65181a7..1bab4bf 100644
--- a/include/ipaddress/base-v6.hpp
+++ b/include/ipaddress/base-v6.hpp
@@ -20,7 +20,11 @@ namespace IPADDRESS_NAMESPACE {
 namespace internal {
 
 IPADDRESS_NODISCARD IPADDRESS_CONSTEXPR IPADDRESS_FORCE_INLINE bool is_invalid_scope_id_symbol(char c) IPADDRESS_NOEXCEPT {
-    return c == '%' || c == '/' || c == ' ' || (c >= '\t' && c <= '\r');
+    return c == '%' || c == '/' 
+#ifndef IPADDRESS_SCOPE_ID_SUPPORT_SPACES
+    || c == ' ' || (c >= '\t' && c <= '\r')
+#endif // IPADDRESS_SCOPE_ID_SUPPORT_SPACES
+    ;
 }
 
 } // namespace IPADDRESS_NAMESPACE::internal
diff --git a/include/ipaddress/errors.hpp b/include/ipaddress/errors.hpp
index e8e8b25..2104a76 100644
--- a/include/ipaddress/errors.hpp
+++ b/include/ipaddress/errors.hpp
@@ -78,7 +78,7 @@ enum class error_code {
     expected_at_most_7_other_parts_with_double_colon, /**< With a double colon present, at most seven other parts are expected. */
     exactly_8_parts_expected_without_double_colon, /**< Without a double colon, exactly eight parts are expected. */
     scope_id_is_too_long, /**< The scope ID in the IPv6 address exceeds the maximum length. */
-    invalid_scope_id, /**< The scope ID in the IPv6 address is invalid. */
+    invalid_scope_id, /**< The scope ID in the IPv6 address is invalid. If for some reason you need to add whitespace support to the scope id, add the following definition IPADDRESS_SCOPE_ID_SUPPORT_SPACES */
 
     // logic errors
     invalid_version, /**< The IP address version does not match the expected version. */
diff --git a/include/ipaddress/uint128.hpp b/include/ipaddress/uint128.hpp
index 524a892..b580ecb 100644
--- a/include/ipaddress/uint128.hpp
+++ b/include/ipaddress/uint128.hpp
@@ -1593,8 +1593,8 @@ class uint128_t final { // NOLINT(cppcoreguidelines-special-member-functions)
         uint128_t result = 0;
         const T* it = begin;
         while (it < end) {
-            auto c = internal::next_char_or_error(it, end, code, error_symbol);
-            if (code != error_code::no_error) {
+            const auto c = internal::next_char_or_error(it, end, code, error_symbol);
+            if (code != error_code::no_error) { // NOLINT(bugprone-branch-clone)
                 return nullptr;
             } else if (c == '\0') {
                 break;
@@ -1613,8 +1613,8 @@ class uint128_t final { // NOLINT(cppcoreguidelines-special-member-functions)
         uint128_t result = 0;
         const T* it = begin;
         while (it < end) {
-            auto c = internal::next_char_or_error(it, end, code, error_symbol);
-            if (code != error_code::no_error) {
+            const auto c = internal::next_char_or_error(it, end, code, error_symbol);
+            if (code != error_code::no_error) { // NOLINT(bugprone-branch-clone)
                 return nullptr;
             } else if (c == '\0') {
                 break;
@@ -1634,8 +1634,8 @@ class uint128_t final { // NOLINT(cppcoreguidelines-special-member-functions)
         int digit = 0;
         const T* it = begin;
         while (it < end) {
-            auto c = internal::next_char_or_error(it, end, code, error_symbol);
-            if (code != error_code::no_error) {
+            const auto c = internal::next_char_or_error(it, end, code, error_symbol);
+            if (code != error_code::no_error) { // NOLINT(bugprone-branch-clone)
                 return nullptr;
             } else if (c == '\0') {
                 break;