diff --git a/Cargo.lock b/Cargo.lock
index 180493c..b2bcf48 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -953,8 +953,8 @@ dependencies = [
 
 [[package]]
 name = "ndc-models"
-version = "0.1.5"
-source = "git+http://github.com/hasura/ndc-spec.git?tag=v0.1.5#78f52768bd02a8289194078a5abc2432c8e3a758"
+version = "0.1.6"
+source = "git+http://github.com/hasura/ndc-spec.git?tag=v0.1.6#d1be19e9cdd86ac7b6ad003ff82b7e5b4e96b84f"
 dependencies = [
  "indexmap 2.2.6",
  "ref-cast",
@@ -967,7 +967,7 @@ dependencies = [
 
 [[package]]
 name = "ndc-sdk"
-version = "0.2.1"
+version = "0.4.0"
 dependencies = [
  "async-trait",
  "axum",
@@ -1000,8 +1000,8 @@ dependencies = [
 
 [[package]]
 name = "ndc-test"
-version = "0.1.5"
-source = "git+http://github.com/hasura/ndc-spec.git?tag=v0.1.5#78f52768bd02a8289194078a5abc2432c8e3a758"
+version = "0.1.6"
+source = "git+http://github.com/hasura/ndc-spec.git?tag=v0.1.6#d1be19e9cdd86ac7b6ad003ff82b7e5b4e96b84f"
 dependencies = [
  "async-trait",
  "clap",
diff --git a/Cargo.toml b/Cargo.toml
index ed995f2..0f61095 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [workspace]
 resolver = "2"
 
-package.version = "0.2.1"
+package.version = "0.4.0"
 package.edition = "2021"
 package.license = "Apache-2.0"
 
diff --git a/crates/sdk/Cargo.toml b/crates/sdk/Cargo.toml
index d24abd8..e41be11 100644
--- a/crates/sdk/Cargo.toml
+++ b/crates/sdk/Cargo.toml
@@ -24,8 +24,6 @@ rustls = ["reqwest/rustls"]
 ndc-test = ["dep:ndc-test"]
 
 [dependencies]
-ndc-models = { git = "http://github.com/hasura/ndc-spec.git", tag = "v0.1.5" }
-ndc-test = { git = "http://github.com/hasura/ndc-spec.git", tag = "v0.1.5", optional = true }
 
 async-trait = "0.1.79"
 axum = { version = "0.6.20", features = ["http2"] }
@@ -33,6 +31,8 @@ axum-extra = "0.8.0"
 bytes = "1.6.0"
 clap = { version = "4.5.4", features = ["derive", "env"] }
 http = "0.2"
+ndc-models = { git = "http://github.com/hasura/ndc-spec.git", tag = "v0.1.6" }
+ndc-test = { git = "http://github.com/hasura/ndc-spec.git", tag = "v0.1.6", optional = true }
 mime = "0.3.17"
 opentelemetry = "0.22.0"
 opentelemetry-http = "0.11.0"
diff --git a/crates/sdk/src/connector/example.rs b/crates/sdk/src/connector/example.rs
index fae3a71..505634e 100644
--- a/crates/sdk/src/connector/example.rs
+++ b/crates/sdk/src/connector/example.rs
@@ -50,6 +50,9 @@ impl Connector for Example {
                     order_by: None,
                     aggregates: None,
                 },
+                exists: models::ExistsCapabilities {
+                    nested_collections: None,
+                },
             },
             mutation: models::MutationCapabilities {
                 transactional: None,
diff --git a/crates/sdk/src/default_main.rs b/crates/sdk/src/default_main.rs
index d2e04c4..c5277e2 100644
--- a/crates/sdk/src/default_main.rs
+++ b/crates/sdk/src/default_main.rs
@@ -449,7 +449,7 @@ mod ndc_test_commands {
             super::get_capabilities::<C>()
                 .await
                 .into_value::<Box<dyn std::error::Error + Send + Sync>>()
-                .map_err(|e| ndc_test::error::Error::OtherError(e))
+                .map_err(ndc_test::error::Error::OtherError)
         }
 
         async fn get_schema(&self) -> Result<ndc_models::SchemaResponse, ndc_test::error::Error> {