diff --git a/src/arith_uint256.h b/src/arith_uint256.h
--- a/src/arith_uint256.h
+++ b/src/arith_uint256.h
@@ -23,7 +23,7 @@
 /** Template base class for unsigned big integers. */
 template <unsigned int BITS> class base_uint {
 protected:
-    enum { WIDTH = BITS / 32 };
+    static constexpr int WIDTH = BITS / 32;
     uint32_t pn[WIDTH];
 
 public:
diff --git a/src/chain.h b/src/chain.h
--- a/src/chain.h
+++ b/src/chain.h
@@ -178,7 +178,7 @@
         return GetHeaderReceivedTime() - GetBlockTime();
     }
 
-    enum { nMedianTimeSpan = 11 };
+    static constexpr int nMedianTimeSpan = 11;
 
     int64_t GetMedianTimePast() const {
         int64_t pmedian[nMedianTimeSpan];
diff --git a/src/consensus/consensus.h b/src/consensus/consensus.h
--- a/src/consensus/consensus.h
+++ b/src/consensus/consensus.h
@@ -36,13 +36,10 @@
 static const int64_t P2SH_ACTIVATION_TIME = 1333234914;
 
 /** Flags for nSequence and nLockTime locks */
-enum {
-    /* Interpret sequence numbers as relative lock-time constraints. */
-    LOCKTIME_VERIFY_SEQUENCE = (1 << 0),
-
-    /* Use GetMedianTimePast() instead of nTime for end point timestamp. */
-    LOCKTIME_MEDIAN_TIME_PAST = (1 << 1),
-};
+/** Interpret sequence numbers as relative lock-time constraints. */
+static constexpr unsigned int LOCKTIME_VERIFY_SEQUENCE = (1 << 0);
+/** Use GetMedianTimePast() instead of nTime for end point timestamp. */
+static constexpr unsigned int LOCKTIME_MEDIAN_TIME_PAST = (1 << 1);
 
 /**
  * Compute the maximum number of sigops operation that can contained in a block
diff --git a/src/protocol.h b/src/protocol.h
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -36,17 +36,16 @@
  */
 class CMessageHeader {
 public:
-    enum {
-        MESSAGE_START_SIZE = 4,
-        COMMAND_SIZE = 12,
-        MESSAGE_SIZE_SIZE = 4,
-        CHECKSUM_SIZE = 4,
-
-        MESSAGE_SIZE_OFFSET = MESSAGE_START_SIZE + COMMAND_SIZE,
-        CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE,
-        HEADER_SIZE = MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE +
-                      CHECKSUM_SIZE
-    };
+    static constexpr size_t MESSAGE_START_SIZE = 4;
+    static constexpr size_t COMMAND_SIZE = 12;
+    static constexpr size_t MESSAGE_SIZE_SIZE = 4;
+    static constexpr size_t CHECKSUM_SIZE = 4;
+    static constexpr size_t MESSAGE_SIZE_OFFSET =
+        MESSAGE_START_SIZE + COMMAND_SIZE;
+    static constexpr size_t CHECKSUM_OFFSET =
+        MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE;
+    static constexpr size_t HEADER_SIZE =
+        MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;
     typedef std::array<uint8_t, MESSAGE_START_SIZE> MessageMagic;
 
     explicit CMessageHeader(const MessageMagic &pchMessageStartIn);
diff --git a/src/uint256.h b/src/uint256.h
--- a/src/uint256.h
+++ b/src/uint256.h
@@ -18,7 +18,7 @@
 /** Template base class for fixed-sized opaque blobs. */
 template <unsigned int BITS> class base_blob {
 protected:
-    enum { WIDTH = BITS / 8 };
+    static constexpr int WIDTH = BITS / 8;
     uint8_t data[WIDTH];
 
 public: