diff --git a/include/psa/crypto_extra.h b/include/psa/crypto_extra.h
index b08f46d..3675ac6 100644
--- a/include/psa/crypto_extra.h
+++ b/include/psa/crypto_extra.h
@@ -224,6 +224,17 @@
 psa_status_t mbedtls_psa_inject_entropy(const unsigned char *seed,
                                         size_t seed_size);
 
+/*
+ * If this option is not turned on, then the function `psa_key_derivation()`
+ * is removed.
+ *
+ * The sole purpose of this option is to make the transition to the new API
+ * smoother. Once the transition is complete it can and should be removed
+ * along with the old API and its implementation.
+ */
+#define PSA_PRE_1_0_KEY_DERIVATION
+
+#if defined(PSA_PRE_1_0_KEY_DERIVATION)
 /** Set up a key derivation operation.
  *
  * FIMXE This function is no longer part of the official API. Its prototype
@@ -280,6 +291,7 @@
                                 const uint8_t *label,
                                 size_t label_length,
                                 size_t capacity);
+#endif /* PSA_PRE_1_0_KEY_DERIVATION */
 
 /* FIXME Deprecated. Remove this as soon as all the tests are updated. */
 #define PSA_ALG_SELECT_RAW                      ((psa_algorithm_t)0x31000001)