diff --git a/doc/tutorial/argument_parser/solution3.cpp b/doc/tutorial/argument_parser/solution3.cpp
index 4f752988..821bf24f 100644
--- a/doc/tutorial/argument_parser/solution3.cpp
+++ b/doc/tutorial/argument_parser/solution3.cpp
@@ -9,7 +9,7 @@ number_type to_number(range_type && range)
 {
     std::string str;
     number_type num;
-    std::ranges::copy(range, std::cpp20::back_inserter(str));
+    std::copy(range.begin(), range.end(), std::back_inserter(str));
     auto res = std::from_chars(&str[0], &str[0] + str.size(), num);
 
     if (res.ec != std::errc{})
diff --git a/doc/tutorial/argument_parser/solution4.cpp b/doc/tutorial/argument_parser/solution4.cpp
index 770e4be9..1ca31773 100644
--- a/doc/tutorial/argument_parser/solution4.cpp
+++ b/doc/tutorial/argument_parser/solution4.cpp
@@ -8,7 +8,7 @@ number_type to_number(range_type && range)
 {
     std::string str;
     number_type num;
-    std::ranges::copy(range, std::cpp20::back_inserter(str));
+    std::copy(range.begin(), range.end(), std::back_inserter(str));
     auto res = std::from_chars(&str[0], &str[0] + str.size(), num);
 
     if (res.ec != std::errc{})
diff --git a/doc/tutorial/argument_parser/solution5.cpp b/doc/tutorial/argument_parser/solution5.cpp
index 27af61e0..cafa7de7 100644
--- a/doc/tutorial/argument_parser/solution5.cpp
+++ b/doc/tutorial/argument_parser/solution5.cpp
@@ -8,7 +8,7 @@ number_type to_number(range_type && range)
 {
     std::string str;
     number_type num;
-    std::ranges::copy(range, std::cpp20::back_inserter(str));
+    std::copy(range.begin(), range.end(), std::back_inserter(str));
     auto res = std::from_chars(&str[0], &str[0] + str.size(), num);
 
     if (res.ec != std::errc{})
diff --git a/doc/tutorial/argument_parser/solution6.cpp b/doc/tutorial/argument_parser/solution6.cpp
index 130e06af..2e14766d 100644
--- a/doc/tutorial/argument_parser/solution6.cpp
+++ b/doc/tutorial/argument_parser/solution6.cpp
@@ -8,7 +8,7 @@ number_type to_number(range_type && range)
 {
     std::string str;
     number_type num;
-    std::ranges::copy(range, std::cpp20::back_inserter(str));
+    std::copy(range.begin(), range.end(), std::back_inserter(str));
     auto res = std::from_chars(&str[0], &str[0] + str.size(), num);
 
     if (res.ec != std::errc{})
diff --git a/include/sharg/argument_parser.hpp b/include/sharg/argument_parser.hpp
index c5325596..705350c0 100644
--- a/include/sharg/argument_parser.hpp
+++ b/include/sharg/argument_parser.hpp
@@ -697,7 +697,7 @@ class argument_parser
         {
             std::string arg{argv[i]};
 
-            if (std::ranges::find(subcommands, arg) != subcommands.end())
+            if (std::find(subcommands.begin(), subcommands.end(), arg) != subcommands.end())
             {
                 sub_parser = std::make_unique<argument_parser>(info.app_name + "-" + arg,
                                                                argc - i,
diff --git a/include/sharg/detail/format_help.hpp b/include/sharg/detail/format_help.hpp
index 1081718c..67080111 100644
--- a/include/sharg/detail/format_help.hpp
+++ b/include/sharg/detail/format_help.hpp
@@ -317,17 +317,14 @@ class format_help : public format_help_base<format_help>
 
         // Tokenize the text.
         std::istringstream iss(text.c_str());
-        std::vector<std::string> tokens;
-        std::ranges::copy(std::istream_iterator<std::string>(iss), std::istream_iterator<std::string>(),
-                          std::cpp20::back_inserter(tokens));
+        std::vector<std::string> tokens{std::istream_iterator<std::string>(iss), std::istream_iterator<std::string>()};
 
         // Print the text.
         assert(pos <= tab);
         std::fill_n(out, tab - pos, ' ');  // go to tab
 
         pos = tab;
-        typedef std::vector<std::string>::const_iterator TConstIter;
-        for (TConstIter it = tokens.begin(); it != tokens.end(); ++it)
+        for (auto it = tokens.begin(); it != tokens.end(); ++it)
         {
             if (it == tokens.begin())
             {
diff --git a/include/sharg/validators.hpp b/include/sharg/validators.hpp
index e5a406ed..cc50b43c 100644
--- a/include/sharg/validators.hpp
+++ b/include/sharg/validators.hpp
@@ -12,7 +12,6 @@
 
 #pragma once
 
-#include <seqan3/std/algorithm>
 #include <fstream>
 #include <regex>
 
@@ -355,7 +354,7 @@ class file_validator_base
         };
 
         // Check if requested extension is present.
-        if (std::ranges::find_if(extensions, case_insensitive_ends_with) == extensions.end())
+        if (std::find_if(extensions.begin(), extensions.end(), case_insensitive_ends_with) == extensions.end())
         {
             throw validation_error{"Expected one of the following valid extensions: " + extensions_str + "! Got " +
                                     all_extensions + " instead!"};
@@ -429,12 +428,15 @@ class file_validator_base
     {
         size_t const suffix_length{suffix.size()};
         size_t const str_length{str.size()};
-        return suffix_length > str_length ?
-               false :
-               std::ranges::equal(str.substr(str_length - suffix_length), suffix, [] (char const chr1, char const chr2)
-               {
-                   return std::tolower(chr1) == std::tolower(chr2);
-               });
+
+        if (suffix_length > str_length)
+            return false;
+
+        for (size_t j = 0, s_start = str_length - suffix_length; j < suffix_length; ++j)
+            if (std::tolower(str[s_start + j]) != std::tolower(suffix[j]))
+                return false;
+
+        return true;
     }
 
     //!\brief Creates a std::string from the extensions list, e.g. "[ext, ext2]".