Additional updates to docs links

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index 884810d..63a13ad 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -141,7 +141,7 @@
 only source of entropy. If you're in that case, please declare OS or hardware
 RNG interfaces with `mbedtls_entropy_add_source()` and/or use an entropy seed
 file created securely during device provisioning. See
-<https://tls.mbed.org/kb/how-to/add-entropy-sources-to-entropy-pool> for more
+<https://mbed-tls.readthedocs.io/en/latest/kb/how-to/add-entropy-sources-to-entropy-pool> for more
 information.
 
 ### Remove helpers for the transition from Mbed TLS 1.3 to Mbed TLS 2.0