diff --git a/src/canonmn_int.cpp b/src/canonmn_int.cpp
index 879a449d..ce7cf9fd 100644
--- a/src/canonmn_int.cpp
+++ b/src/canonmn_int.cpp
@@ -28,8 +28,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! OffOn, multiple tags
     constexpr TagDetails canonOffOn[] = {
@@ -3082,5 +3081,4 @@ namespace Exiv2 {
         return sign * (val + frac) / 32.0F;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/casiomn_int.cpp b/src/casiomn_int.cpp
index c8866ad6..bfbbc207 100644
--- a/src/casiomn_int.cpp
+++ b/src/casiomn_int.cpp
@@ -21,8 +21,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! RecordingMode, tag 0x0001
     constexpr TagDetails casioRecordingMode[] = {
@@ -575,5 +574,4 @@ namespace Exiv2 {
         return os;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/cr2header_int.cpp b/src/cr2header_int.cpp
index a340c214..2f490a40 100644
--- a/src/cr2header_int.cpp
+++ b/src/cr2header_int.cpp
@@ -2,8 +2,7 @@
 
 #include "cr2header_int.hpp"
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
     Cr2Header::Cr2Header(ByteOrder byteOrder)
         : TiffHeaderBase(42, 16, byteOrder, 0x00000010),
           offset2_(0x00000000)
@@ -65,5 +64,4 @@ namespace Exiv2 {
         return isTiffImageTag(tag, group);
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/crwimage_int.cpp b/src/crwimage_int.cpp
index 0f8bfac5..72cae16d 100644
--- a/src/crwimage_int.cpp
+++ b/src/crwimage_int.cpp
@@ -70,8 +70,7 @@ namespace {
     }
 }  // namespace
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     /*
       Mapping table used to decode and encode CIFF tags to/from Exif tags.  Only
@@ -1194,5 +1193,4 @@ namespace Exiv2 {
         return buf;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/fujimn_int.cpp b/src/fujimn_int.cpp
index 4e887718..7821eddc 100644
--- a/src/fujimn_int.cpp
+++ b/src/fujimn_int.cpp
@@ -23,8 +23,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! OffOn, multiple tags
     constexpr TagDetails fujiOffOn[] = {
@@ -373,5 +372,4 @@ namespace Exiv2 {
         return tagInfo_;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/image_int.cpp b/src/image_int.cpp
index e16a1676..deccb560 100644
--- a/src/image_int.cpp
+++ b/src/image_int.cpp
@@ -7,47 +7,42 @@
 #include <cstring>
 #include <cstdio>
 
-namespace Exiv2
-{
-    namespace Internal
+namespace Exiv2::Internal {
+    std::string stringFormat(const char* format, ...)
     {
-        std::string stringFormat(const char* format, ...)
-        {
-            std::string result;
-            std::vector<char> buffer;
-            size_t need = std::strlen(format)*8;  // initial guess
-            int rc = -1;
-
-            // vsnprintf writes at most size (2nd parameter) bytes (including \0)
-            //           returns the number of bytes required for the formatted string excluding \0
-            // the following loop goes through:
-            // one iteration (if 'need' was large enough for the for formatted string)
-            // or two iterations (after the first call to vsnprintf we know the required length)
-            do {
-                buffer.resize(need + 1);
-                va_list args;            // variable arg list
-                va_start(args, format);  // args start after format
-                rc = vsnprintf(&buffer[0], buffer.size(), format, args);
-                va_end(args);     // free the args
-                assert(rc >= 0);  // rc < 0 => we have made an error in the format string
-                if (rc > 0)
-                    need = static_cast<size_t>(rc);
-            } while (buffer.size() <= need);
+        std::string result;
+        std::vector<char> buffer;
+        size_t need = std::strlen(format) * 8;  // initial guess
+        int rc = -1;
 
+        // vsnprintf writes at most size (2nd parameter) bytes (including \0)
+        //           returns the number of bytes required for the formatted string excluding \0
+        // the following loop goes through:
+        // one iteration (if 'need' was large enough for the for formatted string)
+        // or two iterations (after the first call to vsnprintf we know the required length)
+        do {
+            buffer.resize(need + 1);
+            va_list args;            // variable arg list
+            va_start(args, format);  // args start after format
+            rc = vsnprintf(&buffer[0], buffer.size(), format, args);
+            va_end(args);     // free the args
+            assert(rc >= 0);  // rc < 0 => we have made an error in the format string
             if (rc > 0)
-                result = std::string(&buffer[0], need);
-            return result;
-        }
+                need = static_cast<size_t>(rc);
+        } while (buffer.size() <= need);
 
-        std::string indent(int32_t d)
-        {
-            std::string result;
-            if (d > 0)
-                while (d--)
-                    result += "  ";
-            return result;
-        }
+        if (rc > 0)
+            result = std::string(&buffer[0], need);
+        return result;
+    }
 
-    }  // namespace Internal
+    std::string indent(int32_t d)
+    {
+        std::string result;
+        if (d > 0)
+            while (d--)
+                result += "  ";
+        return result;
+    }
 
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/makernote_int.cpp b/src/makernote_int.cpp
index 709901c9..10707a78 100644
--- a/src/makernote_int.cpp
+++ b/src/makernote_int.cpp
@@ -59,16 +59,15 @@ namespace {
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
-        // Function first looks for a config file in current working directory
-        // on Win the file should be named "exiv2.ini"
-        // on Lin the file should be named ".exiv2"
-        // If not found in cwd, we return the default path
-        // which is the user profile path on win and the home dir on linux
-        std::string getExiv2ConfigPath()
-        {
+    // Function first looks for a config file in current working directory
+    // on Win the file should be named "exiv2.ini"
+    // on Lin the file should be named ".exiv2"
+    // If not found in cwd, we return the default path
+    // which is the user profile path on win and the home dir on linux
+    std::string getExiv2ConfigPath()
+    {
 #if defined(_MSC_VER) || defined(__MINGW__)
             std::string inifile("exiv2.ini");
 #else
@@ -90,7 +89,7 @@ namespace Exiv2 {
             currentPath = std::string(pw ? pw->pw_dir : "");
 #endif
             return (currentPath / inifile).string();
-        }
+    }
 
         std::string readExiv2Config(const std::string& section, const std::string& value, const std::string& def)
         {
@@ -1232,8 +1231,7 @@ namespace Exiv2 {
         }
         return -1;
     }
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
 
 // *****************************************************************************
 // local definitions
diff --git a/src/minoltamn_int.cpp b/src/minoltamn_int.cpp
index 2bd70c86..5841786f 100644
--- a/src/minoltamn_int.cpp
+++ b/src/minoltamn_int.cpp
@@ -20,8 +20,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     // -- Standard Minolta Makernotes tags ---------------------------------------------------------------
 
@@ -2471,5 +2470,4 @@ namespace Exiv2 {
         return EXV_PRINT_TAG(minoltaSonyZoneMatching)(os, value, metadata);
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/nikonmn_int.cpp b/src/nikonmn_int.cpp
index 6729d62e..460f1b91 100644
--- a/src/nikonmn_int.cpp
+++ b/src/nikonmn_int.cpp
@@ -22,8 +22,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! OffOn, multiple tags
     constexpr TagDetails nikonOffOn[] = {
@@ -3256,5 +3255,4 @@ fmountlens[] = {
         return os;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/olympusmn_int.cpp b/src/olympusmn_int.cpp
index 9f796cc1..decf3ea5 100644
--- a/src/olympusmn_int.cpp
+++ b/src/olympusmn_int.cpp
@@ -19,8 +19,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! OffOn, multiple tags
     constexpr TagDetails olympusOffOn[] = {
@@ -1666,5 +1665,4 @@ value, const ExifData* metadata)
         return os << v;
     } // OlympusMakerNote::print0x0308
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/orfimage_int.cpp b/src/orfimage_int.cpp
index a0cf92e3..e5d917bb 100644
--- a/src/orfimage_int.cpp
+++ b/src/orfimage_int.cpp
@@ -2,8 +2,7 @@
 
 #include "orfimage_int.hpp"
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     OrfHeader::OrfHeader(ByteOrder byteOrder)
         : TiffHeaderBase(0x4f52, 8, byteOrder, 0x00000008),
@@ -53,5 +52,4 @@ namespace Exiv2 {
         return buf;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/panasonicmn_int.cpp b/src/panasonicmn_int.cpp
index 58413960..1bcbde5c 100644
--- a/src/panasonicmn_int.cpp
+++ b/src/panasonicmn_int.cpp
@@ -16,8 +16,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! Quality, tag 0x0001
     constexpr TagDetails panasonicQuality[] = {
@@ -735,5 +734,4 @@ namespace Exiv2 {
         return tagInfoRaw_;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/pentaxmn_int.cpp b/src/pentaxmn_int.cpp
index 4234ecde..99b0958c 100644
--- a/src/pentaxmn_int.cpp
+++ b/src/pentaxmn_int.cpp
@@ -15,8 +15,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! ShootingMode, tag 0x0001
     constexpr TagDetails pentaxShootingMode[] = {
@@ -1685,5 +1684,4 @@ namespace Exiv2 {
         return tagInfo_;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/pngchunk_int.cpp b/src/pngchunk_int.cpp
index e74004b8..8648cece 100644
--- a/src/pngchunk_int.cpp
+++ b/src/pngchunk_int.cpp
@@ -43,31 +43,28 @@ namespace
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2
-{
-    namespace Internal
+namespace Exiv2::Internal {
+    void PngChunk::decodeIHDRChunk(const DataBuf& data, uint32_t* outWidth, uint32_t* outHeight)
     {
-        void PngChunk::decodeIHDRChunk(const DataBuf& data, uint32_t* outWidth, uint32_t* outHeight)
-        {
-            assert(data.size() >= 8);
+        assert(data.size() >= 8);
 
-            // Extract image width and height from IHDR chunk.
+        // Extract image width and height from IHDR chunk.
 
-            *outWidth = data.read_uint32(0, bigEndian);
-            *outHeight = data.read_uint32(4, bigEndian);
-        }
+        *outWidth = data.read_uint32(0, bigEndian);
+        *outHeight = data.read_uint32(4, bigEndian);
+    }
 
-        void PngChunk::decodeTXTChunk(Image* pImage, const DataBuf& data, TxtChunkType type)
-        {
-            DataBuf key = keyTXTChunk(data);
-            DataBuf arr = parseTXTChunk(data, key.size(), type);
+    void PngChunk::decodeTXTChunk(Image* pImage, const DataBuf& data, TxtChunkType type)
+    {
+        DataBuf key = keyTXTChunk(data);
+        DataBuf arr = parseTXTChunk(data, key.size(), type);
 
 #ifdef EXIV2_DEBUG_MESSAGES
             std::cout << "Exiv2::PngChunk::decodeTXTChunk: TXT chunk data: " << std::string(arr.c_str(), arr.size())
                       << std::endl;
 #endif
             parseChunkContent(pImage, key.c_data(), key.size(), arr);
-        }
+    }
 
         DataBuf PngChunk::decodeTXTChunk(const DataBuf& data, TxtChunkType type)
         {
@@ -632,6 +629,5 @@ namespace Exiv2
 
         }  // PngChunk::writeRawProfile
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
 #endif  // ifdef EXV_HAVE_LIBZ
diff --git a/src/rw2image_int.cpp b/src/rw2image_int.cpp
index 6f16227b..112ab8be 100644
--- a/src/rw2image_int.cpp
+++ b/src/rw2image_int.cpp
@@ -2,8 +2,7 @@
 
 #include "rw2image_int.hpp"
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     Rw2Header::Rw2Header()
         : TiffHeaderBase(0x0055, 24, littleEndian, 0x00000018)
@@ -16,5 +15,4 @@ namespace Exiv2 {
         return {};
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/samsungmn_int.cpp b/src/samsungmn_int.cpp
index ef230fce..417068f8 100644
--- a/src/samsungmn_int.cpp
+++ b/src/samsungmn_int.cpp
@@ -16,8 +16,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! LensType, tag 0xa003
     constexpr TagDetails samsung2LensType[] = {
@@ -179,5 +178,4 @@ namespace Exiv2 {
         return tagInfoPw_;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/sigmamn_int.cpp b/src/sigmamn_int.cpp
index 7bddc45d..a57246ab 100644
--- a/src/sigmamn_int.cpp
+++ b/src/sigmamn_int.cpp
@@ -16,8 +16,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     // Sigma (Foveon) MakerNote Tag Info
     constexpr TagInfo SigmaMakerNote::tagInfo_[] = {
@@ -141,5 +140,4 @@ namespace Exiv2 {
         return os;
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/sonymn_int.cpp b/src/sonymn_int.cpp
index 3ec0a3b4..b7c60e46 100644
--- a/src/sonymn_int.cpp
+++ b/src/sonymn_int.cpp
@@ -20,8 +20,7 @@
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     // -- Standard Sony Makernotes tags ---------------------------------------------------------------
 
@@ -1358,5 +1357,4 @@ namespace Exiv2 {
         return sonyTagCipher(tag,bytes,size,object,false);
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/tags.cpp b/src/tags.cpp
index 7e91153d..3ab23aa9 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -66,8 +66,7 @@ namespace Exiv2 {
 
 } // namespace Exiv2
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     bool TagVocabulary::operator==(const std::string& key) const
     {
@@ -80,8 +79,7 @@ namespace Exiv2 {
                                     N_("Unknown tag"),
                                     ifdIdNotSet, sectionIdNotSet, asciiString, -1, printValue};
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
 
 namespace Exiv2 {
 
diff --git a/src/tags_int.cpp b/src/tags_int.cpp
index bf4944e2..bc4cbe91 100644
--- a/src/tags_int.cpp
+++ b/src/tags_int.cpp
@@ -37,8 +37,7 @@ namespace {
     }
 }  // namespace
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! List of all known Exif groups. Important: Group name (3rd column) must be unique!
     constexpr GroupInfo groupInfo[] = {
@@ -3296,5 +3295,4 @@ namespace Exiv2 {
         return ii->tagList_();
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/tiffcomposite_int.cpp b/src/tiffcomposite_int.cpp
index 6e8a17cd..290b1060 100644
--- a/src/tiffcomposite_int.cpp
+++ b/src/tiffcomposite_int.cpp
@@ -26,8 +26,7 @@ namespace {
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     bool TiffMappingInfo::operator==(const TiffMappingInfo::Key& key) const
     {
@@ -1883,8 +1882,7 @@ namespace Exiv2 {
         return std::make_unique<TiffBinaryElement>(tag, group);
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
 
 // *****************************************************************************
 // local definitions
diff --git a/src/tiffimage_int.cpp b/src/tiffimage_int.cpp
index 305357b8..67d0d292 100644
--- a/src/tiffimage_int.cpp
+++ b/src/tiffimage_int.cpp
@@ -15,8 +15,7 @@
 #define EXV_SIMPLE_BINARY_ARRAY(arrayCfg) (newTiffBinaryArray1<&arrayCfg>)
 #define EXV_COMPLEX_BINARY_ARRAY(arraySet, cfgSelFct) (newTiffBinaryArray2<arraySet, EXV_COUNTOF(arraySet), cfgSelFct>)
 
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     //! Constant for non-encrypted binary arrays
     constexpr CryptFct notEncrypted = nullptr;
@@ -2440,5 +2439,4 @@ namespace Exiv2 {
         }
     }
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal
diff --git a/src/tiffvisitor_int.cpp b/src/tiffvisitor_int.cpp
index 72a944fe..fd3f4323 100644
--- a/src/tiffvisitor_int.cpp
+++ b/src/tiffvisitor_int.cpp
@@ -57,8 +57,7 @@ namespace {
 
 // *****************************************************************************
 // class member definitions
-namespace Exiv2 {
-    namespace Internal {
+namespace Exiv2::Internal {
 
     TiffVisitor::TiffVisitor()
     {
@@ -1699,5 +1698,4 @@ namespace Exiv2 {
 
     } // TiffReader::visitBinaryElement
 
-    }  // namespace Internal
-}  // namespace Exiv2
+}  // namespace Exiv2::Internal