diff --git a/ethers.nimble b/ethers.nimble
index c7f3777..df724fe 100644
--- a/ethers.nimble
+++ b/ethers.nimble
@@ -9,7 +9,7 @@ requires "chronos >= 4.0.0 & < 4.1.0"
 requires "contractabi >= 0.6.0 & < 0.7.0"
 requires "questionable >= 0.10.2 & < 0.11.0"
 requires "json_rpc >= 0.4.0 & < 0.5.0"
-requires "serde >= 0.1.1 & < 0.2.0"
+requires "serde >= 1.2.1 & < 1.3.0"
 requires "stint"
 requires "stew"
 requires "eth"
diff --git a/ethers/providers/jsonrpc/conversions.nim b/ethers/providers/jsonrpc/conversions.nim
index 4abd3da..f23de01 100644
--- a/ethers/providers/jsonrpc/conversions.nim
+++ b/ethers/providers/jsonrpc/conversions.nim
@@ -47,11 +47,6 @@ func fromJson(_: type Address, json: JsonNode): ?!Address =
 func `%`*(integer: UInt256): JsonNode =
   %("0x" & toHex(integer))
 
-func fromJson*(_: type UInt256, json: JsonNode): ?!UInt256 =
-  without result =? UInt256.fromHex(json.getStr()).catch, error:
-    return UInt256.failure error.msg
-  success result
-
 # Transaction
 
 # TODO: add option that ignores none Option[T]
diff --git a/testmodule/providers/jsonrpc/testConversions.nim b/testmodule/providers/jsonrpc/testConversions.nim
index 170a754..4e66491 100644
--- a/testmodule/providers/jsonrpc/testConversions.nim
+++ b/testmodule/providers/jsonrpc/testConversions.nim
@@ -26,8 +26,7 @@ suite "JSON Conversions":
     json["number"] = newJString("")
 
     let blk2 = !Block.fromJson(json)
-    check blk2.number.isSome
-    check blk2.number.get.isZero
+    check blk2.number.isNone
 
   test "missing block hash in Block isNone":
 
@@ -78,8 +77,7 @@ suite "JSON Conversions":
     json["blockNumber"] = newJString("")
     without receipt2 =? TransactionReceipt.fromJson(json):
       fail
-    check receipt2.blockNumber.isSome
-    check receipt2.blockNumber.get.isZero
+    check receipt2.blockNumber.isNone
 
   test "missing block hash in TransactionReceipt isNone":
     let json = %*{