diff --git a/README.md b/README.md
index a117819..d13b738 100644
--- a/README.md
+++ b/README.md
@@ -6,10 +6,11 @@
 
 This is a Javascript library that implements BLS (Boneh-Lynn-Shacham) signatures and supports signature aggregation.
 
->[spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md)
-
+>[spec](https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/beacon-chain.md#bls-signatures)
 >[test vectors](https://github.com/ethereum/eth2.0-spec-tests/tree/master/tests/bls)
 
+##### Notice: *0.3.x* branch and releases follows old [eth2 bls specitification](https://github.com/ethereum/eth2.0-specs/blob/v0.9.4/specs/bls_signature.md)
+
 ## Usage
 - `yarn add @chainsafe/bls`