diff --git a/go.mod b/go.mod
index 4b50d2c..072b73c 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.22.3
 
 require (
 	github.com/celo-org/celo-blockchain v1.8.4
-	github.com/grassrootseconomics/w3-celo v0.17.2
+	github.com/grassrootseconomics/w3-celo v0.18.0
 	golang.org/x/crypto v0.21.0
 )
 
diff --git a/go.sum b/go.sum
index 8042bac..31501bb 100644
--- a/go.sum
+++ b/go.sum
@@ -81,6 +81,8 @@ github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWm
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/grassrootseconomics/w3-celo v0.17.2 h1:sEBlOe/H2F6YvBRTGD/kiObVqUFW7AczbzC8xxsVLDY=
 github.com/grassrootseconomics/w3-celo v0.17.2/go.mod h1:M3KJaj25DspF9siaqNXyamAuzC5DmWXx74tpyPp+R4Y=
+github.com/grassrootseconomics/w3-celo v0.18.0 h1:gO5iK/KP4qrwIGDbKY9k57wnh/dSIvcHTU9lAEHSXbg=
+github.com/grassrootseconomics/w3-celo v0.18.0/go.mod h1:M3KJaj25DspF9siaqNXyamAuzC5DmWXx74tpyPp+R4Y=
 github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d h1:dg1dEPuWpEqDnvIw251EVy4zlP8gWbsGj4BsUKCRpYs=
 github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hdevalence/ed25519consensus v0.0.0-20201207055737-7fde80a9d5ff h1:LeVKjw8pcDQj7WVVnbFvbD7ovcv+r/l15ka1NH6Lswc=
diff --git a/grassroots.go b/grassroots.go
index f899655..9fe45fe 100644
--- a/grassroots.go
+++ b/grassroots.go
@@ -31,6 +31,7 @@ var (
 	entrySig            = w3.MustNewFunc("entry(uint256 _idx)", "address")
 
 	ZeroAddress common.Address
+	ZeroHash    common.Hash
 
 	SarafuNetworkRegistry = w3.A("0xd1FB944748aca327a1ba036B082993D9dd9Bfa0C")
 	CustodialRegistry     = w3.A("0x0cc9f4fff962def35bb34a53691180b13e653030")