diff --git a/Cargo.toml b/Cargo.toml
index 159364c..8171f4a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,9 +10,9 @@ repository = "https://github.com/gauteh/notecard-rs"
 [dependencies]
 defmt = "0.3"
 embedded-hal = "0.2.6"
-heapless = { version = "0.8", features = [ "serde", "ufmt", "defmt-03" ] }
+heapless = { version = "0.7", features = [ "serde", "ufmt-impl", "defmt-impl" ] }
 serde = { version = "1", features = ["derive"], default-features = false }
-serde-json-core = "0.6.0"
+serde-json-core = "0.5.1"
 
 [dev-dependencies]
 base64 = { version = "0.13.0", default-features = false }
diff --git a/src/lib.rs b/src/lib.rs
index 47d1e5e..2f8e9c1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@
 #![feature(type_changing_struct_update)]
 #![cfg_attr(not(test), no_std)]
 
+use core::convert::Infallible;
 use core::marker::PhantomData;
 
 #[allow(unused_imports)]
@@ -117,7 +118,7 @@ impl NoteError {
         NoteError::DeserError(s)
     }
 
-    pub fn string_err(_e: ()) -> NoteError {
+    pub fn string_err(_e: Infallible) -> NoteError {
         NoteError::BufOverflow
     }
 }