diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 5b4e213a..29b2a6e9 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -10,12 +10,12 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        cxx: [g++-4.8, g++-10, clang++-9]
+        cxx: [g++-4.9, g++-10, clang++-9]
         build_type: [Debug, Release]
         std: [11]
         include:
-          - cxx: g++-4.8
-            install: sudo apt install g++-4.8
+          - cxx: g++-4.9
+            install: sudo apt install g++-4.9
           - cxx: g++-8
             build_type: Debug
             std: 14
@@ -64,13 +64,10 @@ jobs:
 
     - name: Add repositories for older GCC
       run: |
-        # Below two repos provide GCC 4.8, 5.5 and 6.4
-        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic main'
-        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic universe'
-        # Below two repos additionally update GCC 6 to 6.5
-        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates main'
-        # sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic-updates universe'
-      if: ${{ matrix.cxx == 'g++-4.8' }}
+        # Below repo provides GCC 4.9.
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ xenial main'
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ xenial universe'
+      if: ${{ matrix.cxx == 'g++-4.9' }}
 
     - name: Add repositories for newer GCC
       run: |
diff --git a/include/fmt/base.h b/include/fmt/base.h
index 4c3233be..017d582b 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -3012,6 +3012,16 @@ template <typename Char = char> struct runtime_format_string {
   basic_string_view<Char> str;
 };
 
+/**
+ * Creates a runtime format string.
+ *
+ * **Example**:
+ *
+ *     // Check format string at runtime instead of compile-time.
+ *     fmt::print(fmt::runtime("{:d}"), "I am not a number");
+ */
+inline auto runtime(string_view s) -> runtime_format_string<> { return {{s}}; }
+
 /// A compile-time format string.
 template <typename Char, typename... Args> class basic_format_string {
  private:
@@ -3053,23 +3063,8 @@ template <typename Char, typename... Args> class basic_format_string {
   auto get() const -> basic_string_view<Char> { return str_; }
 };
 
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-// Workaround broken conversion on older gcc.
-template <typename...> using format_string = string_view;
-inline auto runtime(string_view s) -> string_view { return s; }
-#else
-template <typename... Args>
-using format_string = basic_format_string<char, type_identity_t<Args>...>;
-/**
- * Creates a runtime format string.
- *
- * **Example**:
- *
- *     // Check format string at runtime instead of compile-time.
- *     fmt::print(fmt::runtime("{:d}"), "I am not a number");
- */
-inline auto runtime(string_view s) -> runtime_format_string<> { return {{s}}; }
-#endif
+template <typename... T>
+using format_string = basic_format_string<char, type_identity_t<T>...>;
 
 /// Formats a string and writes the output to `out`.
 template <typename OutputIt,