diff --git a/Cargo.lock b/Cargo.lock
index 68cea58f5..f997fdc91 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -28,7 +28,7 @@ dependencies = [
  "fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.9.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "isatty 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -406,8 +406,8 @@ dependencies = [
  "fetch 0.1.0",
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.10.0-a.0 (git+https://github.com/ethcore/hyper)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "linked-hash-map 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mime 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -577,10 +577,10 @@ dependencies = [
  "ethsync 1.6.0",
  "fetch 0.1.0",
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-ipc-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-ipc-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-reactor 0.1.0",
  "parity-updater 1.6.0",
@@ -604,7 +604,7 @@ dependencies = [
  "ethcore-io 1.6.0",
  "ethcore-rpc 1.6.0",
  "ethcore-util 1.6.0",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-dapps-glue 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-ui 1.6.0",
@@ -623,9 +623,9 @@ dependencies = [
  "ethcore-ipc-codegen 1.6.0",
  "ethcore-ipc-nano 1.6.0",
  "ethcore-util 1.6.0",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git)",
- "jsonrpc-tcp-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
+ "jsonrpc-tcp-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.5.1 (git+https://github.com/ethcore/mio?branch=v0.5.x)",
@@ -946,7 +946,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "jsonrpc-core"
 version = "5.0.0"
-source = "git+https://github.com/ethcore/jsonrpc.git#2187ebc32f67620b000afb03a43a3c2b1020abb3"
+source = "git+https://github.com/ethcore/jsonrpc.git?branch=mio#472abedcbf5198326912bc62d485acb1f5a0989c"
 dependencies = [
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -959,11 +959,11 @@ dependencies = [
 [[package]]
 name = "jsonrpc-http-server"
 version = "7.0.0"
-source = "git+https://github.com/ethcore/jsonrpc.git#2187ebc32f67620b000afb03a43a3c2b1020abb3"
+source = "git+https://github.com/ethcore/jsonrpc.git?branch=mio#472abedcbf5198326912bc62d485acb1f5a0989c"
 dependencies = [
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.10.0-a.0 (git+https://github.com/ethcore/hyper)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-core 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -972,11 +972,11 @@ dependencies = [
 [[package]]
 name = "jsonrpc-ipc-server"
 version = "1.0.0"
-source = "git+https://github.com/ethcore/jsonrpc.git#2187ebc32f67620b000afb03a43a3c2b1020abb3"
+source = "git+https://github.com/ethcore/jsonrpc.git?branch=mio#472abedcbf5198326912bc62d485acb1f5a0989c"
 dependencies = [
  "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -988,21 +988,21 @@ dependencies = [
 [[package]]
 name = "jsonrpc-macros"
 version = "0.2.0"
-source = "git+https://github.com/ethcore/jsonrpc.git#2187ebc32f67620b000afb03a43a3c2b1020abb3"
+source = "git+https://github.com/ethcore/jsonrpc.git?branch=mio#472abedcbf5198326912bc62d485acb1f5a0989c"
 dependencies = [
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "serde 0.8.19 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "jsonrpc-tcp-server"
 version = "1.0.0"
-source = "git+https://github.com/ethcore/jsonrpc.git#2187ebc32f67620b000afb03a43a3c2b1020abb3"
+source = "git+https://github.com/ethcore/jsonrpc.git?branch=mio#472abedcbf5198326912bc62d485acb1f5a0989c"
 dependencies = [
  "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1471,7 +1471,7 @@ dependencies = [
  "ethcore-signer 1.6.0",
  "ethcore-util 1.6.0",
  "futures 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)",
+ "jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2406,11 +2406,11 @@ dependencies = [
 "checksum isatty 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7408a548dc0e406b7912d9f84c261cc533c1866e047644a811c133c56041ac0c"
 "checksum itertools 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)" = "086e1fa5fe48840b1cfdef3a20c7e3115599f8d5c4c87ef32a794a7cdd184d76"
 "checksum itoa 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ae3088ea4baeceb0284ee9eea42f591226e6beaecf65373e41b38d95a1b8e7a1"
-"checksum jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git)" = "<none>"
-"checksum jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git)" = "<none>"
-"checksum jsonrpc-ipc-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git)" = "<none>"
-"checksum jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git)" = "<none>"
-"checksum jsonrpc-tcp-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git)" = "<none>"
+"checksum jsonrpc-core 5.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)" = "<none>"
+"checksum jsonrpc-http-server 7.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)" = "<none>"
+"checksum jsonrpc-ipc-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)" = "<none>"
+"checksum jsonrpc-macros 0.2.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)" = "<none>"
+"checksum jsonrpc-tcp-server 1.0.0 (git+https://github.com/ethcore/jsonrpc.git?branch=mio)" = "<none>"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum language-tags 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a91d884b6667cd606bb5a69aa0c99ba811a115fc68915e7056ec08a46e93199a"
 "checksum lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "49247ec2a285bb3dcb23cbd9c35193c025e7251bfce77c1d5da97e6362dffe7f"
diff --git a/Cargo.toml b/Cargo.toml
index 359ec77b5..c0823be68 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,7 +32,7 @@ app_dirs = "1.1.1"
 fdlimit = "0.1"
 hyper = { version = "0.9", default-features = false }
 ctrlc = { git = "https://github.com/ethcore/rust-ctrlc.git" }
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 ethsync = { path = "sync" }
 ethcore = { path = "ethcore" }
 ethcore-util = { path = "util" }
diff --git a/dapps/Cargo.toml b/dapps/Cargo.toml
index 09c72cb47..af6e2af5d 100644
--- a/dapps/Cargo.toml
+++ b/dapps/Cargo.toml
@@ -13,8 +13,8 @@ rand = "0.3"
 log = "0.3"
 env_logger = "0.3"
 futures = "0.1"
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 hyper = { default-features = false, git = "https://github.com/ethcore/hyper" }
 unicase = "1.3"
 url = "1.0"
diff --git a/rpc/Cargo.toml b/rpc/Cargo.toml
index a11112032..1c8c673f5 100644
--- a/rpc/Cargo.toml
+++ b/rpc/Cargo.toml
@@ -17,10 +17,10 @@ serde_json = "0.8"
 rustc-serialize = "0.3"
 time = "0.1"
 transient-hashmap = "0.1"
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-ipc-server = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-macros = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-ipc-server = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-macros = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 ethcore-io = { path = "../util/io" }
 ethcore-ipc = { path = "../ipc/rpc" }
 ethcore-util = { path = "../util" }
diff --git a/rpc_client/Cargo.toml b/rpc_client/Cargo.toml
index e5c8e9b12..16b513550 100644
--- a/rpc_client/Cargo.toml
+++ b/rpc_client/Cargo.toml
@@ -16,7 +16,7 @@ serde = "0.8"
 serde_json = "0.8"
 tempdir = "0.3.5"
 url = "1.2.0"
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 ws = { git = "https://github.com/ethcore/ws-rs.git", branch = "mio-upstream-stable" }
 ethcore-rpc = { path = "../rpc" }
 ethcore-signer = { path = "../signer" }
diff --git a/rpc_client/src/client.rs b/rpc_client/src/client.rs
index 4f0df5555..5a4568d9e 100644
--- a/rpc_client/src/client.rs
+++ b/rpc_client/src/client.rs
@@ -247,7 +247,7 @@ impl Rpc {
 		self.pending.insert(id, c);
 
 		let request = MethodCall {
-			jsonrpc: Version::V2,
+			jsonrpc: Some(Version::V2),
 			method: method.to_owned(),
 			params: Some(Params::Array(params)),
 			id: Id::Num(id as u64),
diff --git a/signer/Cargo.toml b/signer/Cargo.toml
index 5a24c52bb..66f996694 100644
--- a/signer/Cargo.toml
+++ b/signer/Cargo.toml
@@ -12,7 +12,7 @@ rustc_version = "0.1"
 
 [dependencies]
 rand = "0.3.14"
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 log = "0.3"
 env_logger = "0.3"
 parity-dapps-glue = { version = "1.4", optional = true }
diff --git a/stratum/Cargo.toml b/stratum/Cargo.toml
index 412d08904..76a5db3fd 100644
--- a/stratum/Cargo.toml
+++ b/stratum/Cargo.toml
@@ -11,9 +11,9 @@ ethcore-ipc-codegen = { path = "../ipc/codegen" }
 
 [dependencies]
 log = "0.3"
-jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-macros = { git = "https://github.com/ethcore/jsonrpc.git" }
-jsonrpc-tcp-server = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-macros = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
+jsonrpc-tcp-server = { git = "https://github.com/ethcore/jsonrpc.git", branch="mio" }
 mio = { git = "https://github.com/ethcore/mio", branch = "v0.5.x" }
 ethcore-util = { path = "../util" }
 ethcore-devtools = { path = "../devtools" }