diff --git a/ChangeLog.d/psa_sign_message.txt b/ChangeLog.d/psa_sign_message.txt
new file mode 100644
index 0000000..2d77ec0
--- /dev/null
+++ b/ChangeLog.d/psa_sign_message.txt
@@ -0,0 +1,2 @@
+Features
+   * Implement psa_sign_message() and psa_verify_message().
diff --git a/ChangeLog.d/sha512-output-type.txt b/ChangeLog.d/sha512-output-type.txt
new file mode 100644
index 0000000..eabc67d
--- /dev/null
+++ b/ChangeLog.d/sha512-output-type.txt
@@ -0,0 +1,6 @@
+API changes
+   * The output parameter of mbedtls_sha512_finish_ret, mbedtls_sha512_ret,
+     mbedtls_sha256_finish_ret and mbedtls_sha256_ret now has a pointer type
+     rather than array type. This removes spurious warnings in some compilers
+     when outputting a SHA-384 or SHA-224 hash into a buffer of exactly
+     the hash size.
diff --git a/docs/3.0-migration-guide.d/sha512-output-type.md b/docs/3.0-migration-guide.d/sha512-output-type.md
new file mode 100644
index 0000000..c62a881
--- /dev/null
+++ b/docs/3.0-migration-guide.d/sha512-output-type.md
@@ -0,0 +1,8 @@
+SHA-512 and SHA-256 output type change
+--------------------------
+
+The output parameter of `mbedtls_sha256_finish_ret()`, `mbedtls_sha256_ret()`, `mbedtls_sha512_finish_ret()`, `mbedtls_sha512_ret()` now has a pointer type rather than array type. This makes no difference in terms of C semantics, but removes spurious warnings in some compilers when outputting a SHA-384 hash into a 48-byte buffer or a SHA-224 hash into a 28-byte buffer.
+
+This makes no difference to a vast majority of applications. If your code takes a pointer to one of these functions, you may need to change the type of the pointer.
+
+Alternative implementations of the SHA256 and SHA512 modules must adjust their functions' prototype accordingly.
diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index 9b8d91d..22c2c7d 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -127,13 +127,14 @@
  * \param ctx      The SHA-256 context. This must be initialized
  *                 and have a hash operation started.
  * \param output   The SHA-224 or SHA-256 checksum result.
- *                 This must be a writable buffer of length \c 32 Bytes.
+ *                 This must be a writable buffer of length \c 32 bytes
+ *                 for SHA-256, \c 28 bytes for SHA-224.
  *
  * \return         \c 0 on success.
  * \return         A negative error code on failure.
  */
 int mbedtls_sha256_finish_ret( mbedtls_sha256_context *ctx,
-                               unsigned char output[32] );
+                               unsigned char *output );
 
 /**
  * \brief          This function processes a single data block within
@@ -163,14 +164,15 @@
  * \param input    The buffer holding the data. This must be a readable
  *                 buffer of length \p ilen Bytes.
  * \param ilen     The length of the input data in Bytes.
- * \param output   The SHA-224 or SHA-256 checksum result. This must
- *                 be a writable buffer of length \c 32 Bytes.
+ * \param output   The SHA-224 or SHA-256 checksum result.
+ *                 This must be a writable buffer of length \c 32 bytes
+ *                 for SHA-256, \c 28 bytes for SHA-224.
  * \param is224    Determines which function to use. This must be
  *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
  */
 int mbedtls_sha256_ret( const unsigned char *input,
                         size_t ilen,
-                        unsigned char output[32],
+                        unsigned char *output,
                         int is224 );
 
 #if defined(MBEDTLS_SELF_TEST)
diff --git a/include/mbedtls/sha512.h b/include/mbedtls/sha512.h
index 56cefe1..ef1fa22 100644
--- a/include/mbedtls/sha512.h
+++ b/include/mbedtls/sha512.h
@@ -134,13 +134,14 @@
  * \param ctx      The SHA-512 context. This must be initialized
  *                 and have a hash operation started.
  * \param output   The SHA-384 or SHA-512 checksum result.
- *                 This must be a writable buffer of length \c 64 Bytes.
+ *                 This must be a writable buffer of length \c 64 bytes
+ *                 for SHA-512, \c 48 bytes for SHA-384.
  *
  * \return         \c 0 on success.
  * \return         A negative error code on failure.
  */
 int mbedtls_sha512_finish_ret( mbedtls_sha512_context *ctx,
-                               unsigned char output[64] );
+                               unsigned char *output );
 
 /**
  * \brief          This function processes a single data block within
@@ -171,7 +172,8 @@
  *                 a readable buffer of length \p ilen Bytes.
  * \param ilen     The length of the input data in Bytes.
  * \param output   The SHA-384 or SHA-512 checksum result.
- *                 This must be a writable buffer of length \c 64 Bytes.
+ *                 This must be a writable buffer of length \c 64 bytes
+ *                 for SHA-512, \c 48 bytes for SHA-384.
  * \param is384    Determines which function to use. This must be either
  *                 \c 0 for SHA-512, or \c 1 for SHA-384.
  *
@@ -184,7 +186,7 @@
  */
 int mbedtls_sha512_ret( const unsigned char *input,
                         size_t ilen,
-                        unsigned char output[64],
+                        unsigned char *output,
                         int is384 );
 
 #if defined(MBEDTLS_SELF_TEST)
diff --git a/library/sha256.c b/library/sha256.c
index a94f325..36ab0c1 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -332,7 +332,7 @@
  * SHA-256 final digest
  */
 int mbedtls_sha256_finish_ret( mbedtls_sha256_context *ctx,
-                               unsigned char output[32] )
+                               unsigned char *output )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     uint32_t used;
@@ -401,7 +401,7 @@
  */
 int mbedtls_sha256_ret( const unsigned char *input,
                         size_t ilen,
-                        unsigned char output[32],
+                        unsigned char *output,
                         int is224 )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
diff --git a/library/sha512.c b/library/sha512.c
index 7530629..7d53731 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -380,7 +380,7 @@
  * SHA-512 final digest
  */
 int mbedtls_sha512_finish_ret( mbedtls_sha512_context *ctx,
-                               unsigned char output[64] )
+                               unsigned char *output )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned used;
@@ -453,7 +453,7 @@
  */
 int mbedtls_sha512_ret( const unsigned char *input,
                     size_t ilen,
-                    unsigned char output[64],
+                    unsigned char *output,
                     int is384 )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 7900383..7172c74 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2898,8 +2898,6 @@
 
 #if defined(MBEDTLS_SHA512_C)
 
-typedef int (*finish_sha384_t)(mbedtls_sha512_context*, unsigned char*);
-
 static void ssl_calc_finished_tls_sha384(
                 mbedtls_ssl_context *ssl, unsigned char *buf, int from )
 {
@@ -2958,13 +2956,7 @@
     MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *)
                    sha512.state, sizeof( sha512.state ) );
 #endif
-    /*
-     * For SHA-384, we can save 16 bytes by keeping padbuf 48 bytes long.
-     * However, to avoid stringop-overflow warning in gcc, we have to cast
-     * mbedtls_sha512_finish_ret().
-     */
-    finish_sha384_t finish = (finish_sha384_t)mbedtls_sha512_finish_ret;
-    finish( &sha512, padbuf );
+    mbedtls_sha512_finish_ret( &sha512, padbuf );
 
     mbedtls_sha512_free( &sha512 );
 #endif