diff --git a/Cargo.lock b/Cargo.lock
index 8d98755..48d4d45 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -32,7 +32,7 @@ dependencies = [
 
 [[package]]
 name = "bitflags"
-version = "1.0.4"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -125,14 +125,6 @@ dependencies = [
  "cortex-m 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "generic-array"
-version = "0.11.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "generic-array"
 version = "0.12.0"
@@ -157,16 +149,6 @@ dependencies = [
  "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "heapless"
-version = "0.4.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "as-slice 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "generic-array 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "hash32 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "heapless"
 version = "0.5.0-alpha.2"
@@ -278,9 +260,9 @@ dependencies = [
 [[package]]
 name = "serde-json-core"
 version = "0.0.1"
-source = "git+https://github.com/quartiq/serde-json-core.git?rev=82fdca9#82fdca9eb08183f00480eea289e809e5dd37e9fe"
+source = "git+https://github.com/quartiq/serde-json-core.git?rev=fc764de#fc764deb8dfb82e5cfcc6c5059d8d5c3031e0591"
 dependencies = [
- "heapless 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heapless 0.5.0-alpha.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -299,7 +281,7 @@ name = "smoltcp"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "managed 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -312,12 +294,12 @@ dependencies = [
  "cortex-m-log 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cortex-m-rt 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "cortex-m-rtfm 0.5.0-alpha.1 (git+https://github.com/japaric/cortex-m-rtfm?rev=fafeeb2)",
- "heapless 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heapless 0.5.0-alpha.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "panic-abort 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "panic-semihosting 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde-json-core 0.0.1 (git+https://github.com/quartiq/serde-json-core.git?rev=82fdca9)",
+ "serde-json-core 0.0.1 (git+https://github.com/quartiq/serde-json-core.git?rev=fc764de)",
  "smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "stm32h7 0.7.0",
 ]
@@ -375,7 +357,7 @@ dependencies = [
 "checksum aligned 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d3a316c7ea8e1e9ece54862c992def5a7ac14de9f5832b69d71760680efeeefa"
 "checksum as-slice 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "293dac66b274fab06f95e7efb05ec439a6b70136081ea522d270bc351ae5bb27"
 "checksum bare-metal 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "a3caf393d93b2d453e80638d0674597020cef3382ada454faacd43d1a55a735a"
-"checksum bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
+"checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
 "checksum byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a019b10a2a7cdeb292db131fc8113e57ea2a908f6e7894b0c3c671893b65dbeb"
 "checksum cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "b486ce3ccf7ffd79fdeb678eac06a9e6c09fc88d33836340becb8fffe87c5e33"
 "checksum cortex-m 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)" = "3c0b159a1e8306949579de3698c841dba58058197b65c60807194e4fa1e7a554"
@@ -386,11 +368,9 @@ dependencies = [
 "checksum cortex-m-rtfm 0.5.0-alpha.1 (git+https://github.com/japaric/cortex-m-rtfm?rev=fafeeb2)" = "<none>"
 "checksum cortex-m-rtfm-macros 0.5.0-alpha.1 (git+https://github.com/japaric/cortex-m-rtfm?rev=fafeeb2)" = "<none>"
 "checksum cortex-m-semihosting 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "165f3f86f4d1031351a6c9dc8d5a3f8fae2050f9dd6ef925e3d675c232cc0e46"
-"checksum generic-array 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8107dafa78c80c848b71b60133954b4a58609a3a1a5f9af037ecc7f67280f369"
 "checksum generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c0f28c2f5bfb5960175af447a2da7c18900693738343dc896ffbcabd9839592"
 "checksum generic-array 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d3904420fad470d07ec9e4dbac00c2dc46765d3c4eb6cd1d9bb4d9c8a09c5f6"
 "checksum hash32 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "12d790435639c06a7b798af9e1e331ae245b7ef915b92f70a39b4cf8c00686af"
-"checksum heapless 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "e1ae80bbc62401ae8096976857172507cadbd2200f36670e5144634360a05959"
 "checksum heapless 0.5.0-alpha.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c50e9f50ed4098bca126410960080738c3dd4cbea45812c15cf8aa02a9cfded1"
 "checksum log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c84ec4b527950aa83a329754b01dbe3f58361d1c5efacd1f6d68c494d08a17c6"
 "checksum managed 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fdcec5e97041c7f0f1c5b7d93f12e57293c831c646f4cc7a5db59460c7ea8de6"
@@ -406,7 +386,7 @@ dependencies = [
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 "checksum serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)" = "32746bf0f26eab52f06af0d0aa1984f641341d06d8d673c693871da2d188c9be"
-"checksum serde-json-core 0.0.1 (git+https://github.com/quartiq/serde-json-core.git?rev=82fdca9)" = "<none>"
+"checksum serde-json-core 0.0.1 (git+https://github.com/quartiq/serde-json-core.git?rev=fc764de)" = "<none>"
 "checksum serde_derive 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)" = "46a3223d0c9ba936b61c0d2e3e559e3217dbfb8d65d06d26e8b3c25de38bae3e"
 "checksum smoltcp 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fef582369edb298c6c41319a544ca9c4e83622f226055ccfcb35974fbb55ed34"
 "checksum stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dba1a27d3efae4351c8051072d619e3ade2820635c3958d826bfea39d59b54c8"
diff --git a/Cargo.toml b/Cargo.toml
index 9601e31..3fdd336 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,12 +34,12 @@ log = "0.4"
 panic-abort = "0.3"
 panic-semihosting = { version = "0.5.2", optional = true }
 serde = { version = "1.0", features = ["derive"], default-features = false }
-heapless = { version = "0.4" }
+heapless = { version = "0.5.0-alpha.2" }
 
 [dependencies.serde-json-core]
 # version = "0.0"
 git = "https://github.com/quartiq/serde-json-core.git"
-rev = "82fdca9"
+rev = "fc764de"
 
 [dependencies.stm32h7]
 path = "../stm32-rs/stm32h7"