diff --git a/beacon_chain/spec/datatypes/base.nim b/beacon_chain/spec/datatypes/base.nim
index 6f6173d62..80c5b1185 100644
--- a/beacon_chain/spec/datatypes/base.nim
+++ b/beacon_chain/spec/datatypes/base.nim
@@ -63,7 +63,7 @@ const
   MAX_GRAFFITI_SIZE = 32
   FAR_FUTURE_SLOT* = (not 0'u64).Slot
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/p2p-interface.md#configuration
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/p2p-interface.md#configuration
   MAXIMUM_GOSSIP_CLOCK_DISPARITY* = 500.millis
 
   SLOTS_PER_ETH1_VOTING_PERIOD* =
@@ -72,7 +72,7 @@ const
   DEPOSIT_CONTRACT_TREE_DEPTH* = 32
   BASE_REWARDS_PER_EPOCH* = 4
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/validator.md#misc
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#misc
   ATTESTATION_SUBNET_COUNT* = 64
 
   # https://github.com/ethereum/eth2.0-specs/pull/2101
@@ -114,7 +114,7 @@ template maxSize*(n: int) {.pragma.}
 type
   # Domains
   # ---------------------------------------------------------------
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#domain-types
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#domain-types
   DomainType* = enum
     DOMAIN_BEACON_PROPOSER = 0
     DOMAIN_BEACON_ATTESTER = 1
@@ -124,7 +124,7 @@ type
     DOMAIN_SELECTION_PROOF = 5
     DOMAIN_AGGREGATE_AND_PROOF = 6
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#custom-types
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#custom-types
   Domain* = array[32, byte]
 
   # https://github.com/nim-lang/Nim/issues/574 and be consistent across
@@ -148,7 +148,7 @@ type
 
   Gwei* = uint64
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#proposerslashing
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#proposerslashing
   ProposerSlashing* = object
     signed_header_1*: SignedBeaconBlockHeader
     signed_header_2*: SignedBeaconBlockHeader
@@ -160,7 +160,7 @@ type
     signed_header_1*: TrustedSignedBeaconBlockHeader
     signed_header_2*: TrustedSignedBeaconBlockHeader
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#attesterslashing
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#attesterslashing
   AttesterSlashing* = object
     attestation_1*: IndexedAttestation
     attestation_2*: IndexedAttestation
@@ -172,7 +172,7 @@ type
     attestation_1*: TrustedIndexedAttestation
     attestation_2*: TrustedIndexedAttestation
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#indexedattestation
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#indexedattestation
   IndexedAttestation* = object
     attesting_indices*: List[uint64, Limit MAX_VALIDATORS_PER_COMMITTEE]
     data*: AttestationData
@@ -188,7 +188,7 @@ type
 
   CommitteeValidatorsBits* = BitList[Limit MAX_VALIDATORS_PER_COMMITTEE]
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#attestation
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#attestation
   Attestation* = object
     aggregation_bits*: CommitteeValidatorsBits
     data*: AttestationData
@@ -204,17 +204,17 @@ type
 
   ForkDigest* = distinct array[4, byte]
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#forkdata
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#forkdata
   ForkData* = object
     current_version*: Version
     genesis_validators_root*: Eth2Digest
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#checkpoint
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#checkpoint
   Checkpoint* = object
     epoch*: Epoch
     root*: Eth2Digest
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#AttestationData
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#AttestationData
   AttestationData* = object
     slot*: Slot
 
@@ -227,20 +227,20 @@ type
     source*: Checkpoint
     target*: Checkpoint
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#deposit
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#deposit
   Deposit* = object
     proof*: array[DEPOSIT_CONTRACT_TREE_DEPTH + 1, Eth2Digest] ##\
     ## Merkle path to deposit root
 
     data*: DepositData
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#depositmessage
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#depositmessage
   DepositMessage* = object
     pubkey*: ValidatorPubKey
     withdrawal_credentials*: Eth2Digest
     amount*: Gwei
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#depositdata
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#depositdata
   DepositData* = object
     pubkey*: ValidatorPubKey
     withdrawal_credentials*: Eth2Digest
@@ -249,14 +249,14 @@ type
     # if the deposit should be added or not during processing
     signature*: ValidatorSig  # Signing over DepositMessage
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#voluntaryexit
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#voluntaryexit
   VoluntaryExit* = object
     epoch*: Epoch ##\
     ## Earliest epoch when voluntary exit can be processed
 
     validator_index*: uint64
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#beaconblock
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#beaconblock
   BeaconBlock* = object
     ## For each slot, a proposer is chosen from the validator pool to propose
     ## a new block. Once the block as been proposed, it is transmitted to
@@ -312,7 +312,7 @@ type
     state_root*: Eth2Digest ##\
     body*: TrustedBeaconBlockBody
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#beaconblockheader
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#beaconblockheader
   BeaconBlockHeader* = object
     slot*: Slot
     proposer_index*: uint64
@@ -320,14 +320,14 @@ type
     state_root*: Eth2Digest
     body_root*: Eth2Digest
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#signingdata
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#signingdata
   SigningData* = object
     object_root*: Eth2Digest
     domain*: Domain
 
   GraffitiBytes* = distinct array[MAX_GRAFFITI_SIZE, byte]
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#beaconblockbody
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#beaconblockbody
   BeaconBlockBody* = object
     randao_reveal*: ValidatorSig
     eth1_data*: Eth1Data
@@ -386,7 +386,7 @@ type
   SomeSignedBeaconBlockHeader* = SignedBeaconBlockHeader | TrustedSignedBeaconBlockHeader
   SomeSignedVoluntaryExit* = SignedVoluntaryExit | TrustedSignedVoluntaryExit
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#beaconstate
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#beaconstate
   BeaconState* = object
     # Versioning
     genesis_time*: uint64
@@ -450,7 +450,7 @@ type
     pubkey*: ValidatorPubKey
     withdrawal_credentials*: Eth2Digest
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#validator
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#validator
   Validator* = object
     pubkey*: ValidatorPubKey
 
@@ -472,7 +472,7 @@ type
     withdrawable_epoch*: Epoch ##\
     ## When validator can withdraw or transfer funds
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#pendingattestation
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#pendingattestation
   PendingAttestation* = object
     aggregation_bits*: CommitteeValidatorsBits
     data*: AttestationData
@@ -481,12 +481,12 @@ type
 
     proposer_index*: uint64
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#historicalbatch
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#historicalbatch
   HistoricalBatch* = object
     block_roots* : array[SLOTS_PER_HISTORICAL_ROOT, Eth2Digest]
     state_roots* : array[SLOTS_PER_HISTORICAL_ROOT, Eth2Digest]
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#fork
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#fork
   Fork* = object
     previous_version*: Version
     current_version*: Version
@@ -494,13 +494,13 @@ type
     epoch*: Epoch ##\
     ## Epoch of latest fork
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#eth1data
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#eth1data
   Eth1Data* = object
     deposit_root*: Eth2Digest
     deposit_count*: uint64
     block_hash*: Eth2Digest
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#signedvoluntaryexit
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#signedvoluntaryexit
   SignedVoluntaryExit* = object
     message*: VoluntaryExit
     signature*: ValidatorSig
@@ -509,7 +509,7 @@ type
     message*: VoluntaryExit
     signature*: TrustedSig
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#signedbeaconblock
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#signedbeaconblock
   SignedBeaconBlock* = object
     message*: BeaconBlock
     signature*: ValidatorSig
@@ -541,7 +541,7 @@ type
 
     root* {.dontSerialize.}: Eth2Digest # cached root of signed beacon block
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#signedbeaconblockheader
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#signedbeaconblockheader
   SignedBeaconBlockHeader* = object
     message*: BeaconBlockHeader
     signature*: ValidatorSig
@@ -550,13 +550,13 @@ type
     message*: BeaconBlockHeader
     signature*: TrustedSig
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/validator.md#aggregateandproof
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#aggregateandproof
   AggregateAndProof* = object
     aggregator_index*: uint64
     aggregate*: Attestation
     selection_proof*: ValidatorSig
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/validator.md#signedaggregateandproof
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#signedaggregateandproof
   SignedAggregateAndProof* = object
     message*: AggregateAndProof
     signature*: ValidatorSig
@@ -573,12 +573,12 @@ type
     beacon_proposer_indices*: Table[Slot, Option[ValidatorIndex]]
 
   # This matches the mutable state of the Solidity deposit contract
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/solidity_deposit_contract/deposit_contract.sol
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/solidity_deposit_contract/deposit_contract.sol
   DepositContractState* = object
     branch*: array[DEPOSIT_CONTRACT_TREE_DEPTH, Eth2Digest]
     deposit_count*: array[32, byte] # Uint256
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#validator
+  # https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#validator
   ValidatorStatus* = object
     # This is a validator without the expensive, immutable, append-only parts