diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 9f965c1d7..c14228dc1 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -175,7 +175,6 @@ These configurations are updated for releases, but may be out of sync during `de
 | Name | Value |
 | - | - |
 | `DEPOSIT_CONTRACT_TREE_DEPTH` | `2**5` (= 32) |
-| `DEPOSIT_FORK_VERSION` | `b'\x00' * 4` |
 
 ### Gwei values
 
@@ -634,9 +633,9 @@ The `hash` function is SHA256.
 ### `bls_domain`
 
 ```python
-def bls_domain(domain_type: int, fork_version: bytes) -> int:
+def bls_domain(domain_type: int, fork_version=b'\x00\x00\x00\x00') -> int:
     """
-    Return the bls domain given by the ``domain_type`` and 4 byte ``fork_version``..
+    Return the bls domain given by the ``domain_type`` and optional 4 byte ``fork_version`` (defaults to zero).
     """
     return bytes_to_int(int_to_bytes(domain_type, length=4) + fork_version)
 ```
@@ -1779,7 +1778,7 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
         # Verify the deposit signature (proof of possession)
         # Note: deposits are valid across forks, hence the deposit domain is retrieved directly from `bls_domain`
         if not bls_verify(
-            pubkey, signing_root(deposit.data), deposit.data.signature, bls_domain(DOMAIN_DEPOSIT, DEPOSIT_FORK_VERSION)
+            pubkey, signing_root(deposit.data), deposit.data.signature, bls_domain(DOMAIN_DEPOSIT)
         ):
             return
 
diff --git a/specs/validator/0_beacon-chain-validator.md b/specs/validator/0_beacon-chain-validator.md
index 49bb4fc3a..f8272d446 100644
--- a/specs/validator/0_beacon-chain-validator.md
+++ b/specs/validator/0_beacon-chain-validator.md
@@ -98,7 +98,7 @@ To submit a deposit:
 * Pack the validator's [initialization parameters](#initialization) into `deposit_data`, a [`DepositData`](../core/0_beacon-chain.md#depositdata) SSZ object.
 * Let `amount` be the amount in Gwei to be deposited by the validator where `MIN_DEPOSIT_AMOUNT <= amount <= MAX_EFFECTIVE_BALANCE`.
 * Set `deposit_data.amount = amount`.
-* Let `signature` be the result of `bls_sign` of the `signing_root(deposit_data)` with `domain=bls_domain(DOMAIN_DEPOSIT, DEPOSIT_FORK_VERSION)`. (Deposits are valid regardless of fork version, hence the static fork version being directly passed into `bls_domain`).
+* Let `signature` be the result of `bls_sign` of the `signing_root(deposit_data)` with `domain=bls_domain(DOMAIN_DEPOSIT)`. (Deposits are valid regardless of fork version, `bls_domain` will default to zeroes there).
 * Send a transaction on the Ethereum 1.0 chain to `DEPOSIT_CONTRACT_ADDRESS` executing `def deposit(pubkey: bytes[48], withdrawal_credentials: bytes[32], signature: bytes[96])` along with a deposit of `amount` Gwei.
 
 *Note*: Deposits made for the same `pubkey` are treated as for the same validator. A singular `Validator` will be added to `state.validator_registry` with each additional deposit amount added to the validator's balance. A validator can only be activated when total deposits for the validator pubkey meet or exceed `MAX_EFFECTIVE_BALANCE`.
diff --git a/test_libs/pyspec/tests/helpers.py b/test_libs/pyspec/tests/helpers.py
index eebbd2daf..06ca8a1d5 100644
--- a/test_libs/pyspec/tests/helpers.py
+++ b/test_libs/pyspec/tests/helpers.py
@@ -147,7 +147,6 @@ def build_deposit_data(state, pubkey, privkey, amount):
         privkey=privkey,
         domain=bls_domain(
             spec.DOMAIN_DEPOSIT,
-            spec.DEPOSIT_FORK_VERSION,
         )
     )
     deposit_data.signature = signature