diff --git a/include/polarssl/check_config.h b/include/polarssl/check_config.h
index 1062434..a668cf8 100644
--- a/include/polarssl/check_config.h
+++ b/include/polarssl/check_config.h
@@ -30,6 +30,11 @@
 #ifndef POLARSSL_CHECK_CONFIG_H
 #define POLARSSL_CHECK_CONFIG_H
 
+#if defined(POLARSSL_DEPRECATED_WARNING) && \
+    !defined(__GCC__) && !defined(__clang__)
+#error "POLARSSL_DEPRECATED_WARNING only works with GCC and Clang"
+#endif
+
 #if defined(POLARSSL_AESNI_C) && !defined(POLARSSL_HAVE_ASM)
 #error "POLARSSL_AESNI_C defined, but not all prerequisites"
 #endif
diff --git a/include/polarssl/cipher.h b/include/polarssl/cipher.h
index 6773f61..ef8d281 100644
--- a/include/polarssl/cipher.h
+++ b/include/polarssl/cipher.h
@@ -372,6 +372,12 @@
  */
 int cipher_init_ctx( cipher_context_t *ctx, const cipher_info_t *cipher_info );
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 /**
  * \brief               Free the cipher-specific context of ctx. Freeing ctx
  *                      itself remains the responsibility of the caller.
@@ -382,7 +388,9 @@
  *
  * \returns             0
  */
-int cipher_free_ctx( cipher_context_t *ctx );
+int cipher_free_ctx( cipher_context_t *ctx ) DEPRECATED;
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 
 /**
  * \brief               Returns the block size of the given cipher.
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index be7da28..63db5ee 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -179,6 +179,34 @@
 //#define POLARSSL_PLATFORM_FPRINTF_ALT
 //#define POLARSSL_PLATFORM_PRINTF_ALT
 //#define POLARSSL_PLATFORM_SNPRINTF_ALT
+
+/**
+ * \def POLARSSL_DEPRECATED_WARNING
+ *
+ * Mark deprecated functions so that they generate a warning if used.
+ * Functions deprecated in one version will usually be removed in the next
+ * version. You can enable this to help you prepare the transition to a new
+ * major version by making sure your code is not using these functions.
+ *
+ * This only works with GCC and Clang. With other compilers, you may want to
+ * use POLARSSL_DEPRECATED_REMOVED
+ *
+ * Uncomment to get warnings on using deprecated functions.
+ */
+//#define POLARSSL_DEPRECATED_WARNING
+
+/**
+ * \def POLARSSL_DEPRECATED_REMOVED
+ *
+ * Remove deprecated functions so that they generate an error if used.
+ * Functions deprecated in one version will usually be removed in the next
+ * version. You can enable this to help you prepare the transition to a new
+ * major version by making sure your code is not using these functions.
+ *
+ * Uncomment to get errors on using deprecated functions.
+ */
+//#define POLARSSL_DEPRECATED_REMOVED
+
 /* \} name SECTION: System support */
 
 /**
diff --git a/include/polarssl/md.h b/include/polarssl/md.h
index 95da80b..303aee8 100644
--- a/include/polarssl/md.h
+++ b/include/polarssl/md.h
@@ -200,6 +200,12 @@
  */
 int md_init_ctx( md_context_t *ctx, const md_info_t *md_info );
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 /**
  * \brief          Free the message-specific context of ctx. Freeing ctx itself
  *                 remains the responsibility of the caller.
@@ -210,7 +216,9 @@
  *
  * \returns        0
  */
-int md_free_ctx( md_context_t *ctx );
+int md_free_ctx( md_context_t *ctx ) DEPRECATED;
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 
 /**
  * \brief           Returns the size of the message digest output.
diff --git a/include/polarssl/memory.h b/include/polarssl/memory.h
index 8312beb..8b8ac5d 100644
--- a/include/polarssl/memory.h
+++ b/include/polarssl/memory.h
@@ -37,16 +37,26 @@
 #include "platform.h"
 #include "memory_buffer_alloc.h"
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 /**
  * \brief   Set malloc() / free() callback
  *
  * \deprecated Use platform_set_malloc_free instead
  */
 int memory_set_own( void * (*malloc_func)( size_t ),
+                    void (*free_func)( void * ) ) DEPRECATED;
+int memory_set_own( void * (*malloc_func)( size_t ),
                     void (*free_func)( void * ) )
 {
     return platform_set_malloc_free( malloc_func, free_func );
 }
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 
 
 #endif /* memory.h */
diff --git a/include/polarssl/pbkdf2.h b/include/polarssl/pbkdf2.h
index e842c83..28987b3 100644
--- a/include/polarssl/pbkdf2.h
+++ b/include/polarssl/pbkdf2.h
@@ -45,6 +45,12 @@
 extern "C" {
 #endif
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 /**
  * \brief          PKCS#5 PBKDF2 using HMAC
  *
@@ -64,7 +70,7 @@
 int pbkdf2_hmac( md_context_t *ctx, const unsigned char *password,
                  size_t plen, const unsigned char *salt, size_t slen,
                  unsigned int iteration_count,
-                 uint32_t key_length, unsigned char *output );
+                 uint32_t key_length, unsigned char *output ) DEPRECATED;
 
 /**
  * \brief          Checkup routine
@@ -73,7 +79,9 @@
  *
  * \return         0 if successful, or 1 if the test failed
  */
-int pbkdf2_self_test( int verbose );
+int pbkdf2_self_test( int verbose ) DEPRECATED;
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 
 #ifdef __cplusplus
 }
diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 8e82137..cd9f770 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -1213,6 +1213,12 @@
 int ssl_set_own_cert( ssl_context *ssl, x509_crt *own_cert,
                        pk_context *pk_key );
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 #if defined(POLARSSL_RSA_C)
 /**
  * \brief          Set own certificate chain and private RSA key
@@ -1230,7 +1236,7 @@
  * \return          0 on success, or a specific error code.
  */
 int ssl_set_own_cert_rsa( ssl_context *ssl, x509_crt *own_cert,
-                          rsa_context *rsa_key );
+                          rsa_context *rsa_key ) DEPRECATED;
 #endif /* POLARSSL_RSA_C */
 
 /**
@@ -1261,7 +1267,9 @@
                           void *rsa_key,
                           rsa_decrypt_func rsa_decrypt,
                           rsa_sign_func rsa_sign,
-                          rsa_key_len_func rsa_key_len );
+                          rsa_key_len_func rsa_key_len ) DEPRECATED;
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 #endif /* POLARSSL_X509_CRT_PARSE_C */
 
 #if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 9dda082..0dece06 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -225,6 +225,12 @@
  */
 int x509_serial_gets( char *buf, size_t size, const x509_buf *serial );
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
+#if defined(POLARSSL_DEPRECATED_WARNING)
+#define DEPRECATED    __attribute__((deprecated))
+#else
+#define DEPRECATED
+#endif
 /**
  * \brief          Give an known OID, return its descriptive string.
  *
@@ -237,7 +243,7 @@
  * \return         Return a string if the OID is known,
  *                 or NULL otherwise.
  */
-const char *x509_oid_get_description( x509_buf *oid );
+const char *x509_oid_get_description( x509_buf *oid ) DEPRECATED;
 
 /**
  * \brief          Give an OID, return a string version of its OID number.
@@ -251,7 +257,9 @@
  * \return         Length of the string written (excluding final NULL) or
  *                 POLARSSL_ERR_OID_BUF_TO_SMALL in case of error
  */
-int x509_oid_get_numeric_string( char *buf, size_t size, x509_buf *oid );
+int x509_oid_get_numeric_string( char *buf, size_t size, x509_buf *oid ) DEPRECATED;
+#undef DEPRECATED
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 
 /**
  * \brief          Check a given x509_time against the system time and check
diff --git a/library/cipher.c b/library/cipher.c
index 516fa00..b69d331 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -165,13 +165,14 @@
     return( 0 );
 }
 
-/* compatibility wrapper */
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 int cipher_free_ctx( cipher_context_t *ctx )
 {
     cipher_free( ctx );
 
     return( 0 );
 }
+#endif
 
 int cipher_setkey( cipher_context_t *ctx, const unsigned char *key,
         int key_length, const operation_t operation )
diff --git a/library/md.c b/library/md.c
index fbdab91..cf4d7e3 100644
--- a/library/md.c
+++ b/library/md.c
@@ -203,12 +203,14 @@
     return( 0 );
 }
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 int md_free_ctx( md_context_t *ctx )
 {
     md_free( ctx );
 
     return( 0 );
 }
+#endif
 
 int md_starts( md_context_t *ctx )
 {
diff --git a/library/pbkdf2.c b/library/pbkdf2.c
index b4ef195..783e4a8 100644
--- a/library/pbkdf2.c
+++ b/library/pbkdf2.c
@@ -41,6 +41,7 @@
 #include "polarssl/pbkdf2.h"
 #include "polarssl/pkcs5.h"
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 int pbkdf2_hmac( md_context_t *ctx, const unsigned char *password, size_t plen,
                  const unsigned char *salt, size_t slen,
                  unsigned int iteration_count,
@@ -49,12 +50,15 @@
     return pkcs5_pbkdf2_hmac( ctx, password, plen, salt, slen, iteration_count,
                               key_length, output );
 }
+#endif
 
 #if defined(POLARSSL_SELF_TEST)
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 int pbkdf2_self_test( int verbose )
 {
     return pkcs5_self_test( verbose );
 }
+#endif
 #endif /* POLARSSL_SELF_TEST */
 
 #endif /* POLARSSL_PBKDF2_C */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 77bb9ad..515b903 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3976,6 +3976,7 @@
     return( 0 );
 }
 
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 #if defined(POLARSSL_RSA_C)
 int ssl_set_own_cert_rsa( ssl_context *ssl, x509_crt *own_cert,
                            rsa_context *rsa_key )
@@ -4033,6 +4034,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_DEPRECATED_REMOVED */
 #endif /* POLARSSL_X509_CRT_PARSE_C */
 
 #if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
diff --git a/library/x509.c b/library/x509.c
index b35663d..922f023 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -880,6 +880,7 @@
 /*
  * Return an informational string describing the given OID
  */
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 const char *x509_oid_get_description( x509_buf *oid )
 {
     const char *desc = NULL;
@@ -892,12 +893,15 @@
 
     return( desc );
 }
+#endif
 
 /* Return the x.y.z.... style numeric string for the given OID */
+#if ! defined(POLARSSL_DEPRECATED_REMOVED)
 int x509_oid_get_numeric_string( char *buf, size_t size, x509_buf *oid )
 {
     return oid_get_numeric_string( buf, size, oid );
 }
+#endif
 
 /*
  * Return 0 if the x509_time is still valid, or 1 otherwise.