diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4ce55c8..3ff1009 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,7 +3,7 @@ name: CI
 env:
   CARGO_TERM_COLOR: always
   CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
-  NIGHTLY: nightly-2025-11-06
+  NIGHTLY: nightly-2026-04-17
 
 on:
   push:
@@ -26,14 +26,14 @@ jobs:
       - name: Install MSRV toolchain
         uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.88"
+          toolchain: "1.89"
 
       - uses: Swatinem/rust-cache@v2
         with:
           # A stable compiler update should automatically not reuse old caches.
           # Add the MSRV as a stable cache key too so bumping it also gets us a
           # fresh cache.
-          shared-key: msrv1.88
+          shared-key: msrv1.89
 
       - name: Run checks
         run: cargo check --all-features
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58513d7..37f4f63 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@ Breaking changes:
 
 - Upgrade reqwest to 0.13.
   - The `reqwest-*` cargo features were updated to match the changes upstream.
+- Upgrade ruma to 0.15.0.
+  - Bump the MSRV to 1.89.
 
 ## 0.17.0
 
diff --git a/Cargo.toml b/Cargo.toml
index e1993e9..e2cd344 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,7 @@ readme = "README.md"
 repository = "https://github.com/ruma/ruma-client"
 version = "0.17.0"
 edition = "2024"
-rust-version = "1.88"
+rust-version = "1.89"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -21,7 +21,7 @@ ignored = [
 ]
 
 [features]
-client-api = ["dep:as_variant", "ruma/client-api-c"]
+client-api = ["ruma/client-api-c"]
 
 # HTTP clients
 hyper = ["dep:http-body-util", "dep:hyper", "dep:hyper-util"]
@@ -36,7 +36,7 @@ reqwest-rustls = ["reqwest", "reqwest?/rustls"]
 reqwest-rustls-no-provider = ["reqwest", "reqwest?/rustls-no-provider"]
 
 [dependencies]
-as_variant = { version = "1.2.0", optional = true }
+as_variant = "1.2.0"
 assign = "1.1.1"
 async-stream = "0.3.0"
 bytes = "1.0.1"
@@ -48,11 +48,11 @@ hyper-rustls = { version = "0.27.1", optional = true, default-features = false }
 hyper-tls = { version = "0.6.0", optional = true }
 hyper-util = { version = "0.1.3", optional = true, features = ["client-legacy", "http1", "http2", "tokio"] }
 reqwest = { version = "0.13", optional = true, default-features = false }
-ruma = { version = "0.14.1", features = ["api"] }
+ruma = { version = "0.15.0", features = ["api"] }
 tracing = { version = "0.1.30", default-features = false, features = ["std"] }
 
 [dev-dependencies]
-ruma = { version = "0.14.1", features = ["client-api-c"] }
+ruma = { version = "0.15.0", features = ["client-api-c"] }
 tokio-stream = "0.1.8"
 
 [lints.rust]
diff --git a/src/client.rs b/src/client.rs
index 35e598e..fc1fda2 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -16,7 +16,7 @@ use ruma::{
             account::register::{self, RegistrationKind},
             session::login::{self, v3::LoginInfo},
             sync::sync_events,
-            uiaa::UserIdentifier,
+            uiaa::{MatrixUserIdentifier, UserIdentifier},
         },
         path_builder::{PathBuilder, SinglePath, VersionHistory},
     },
@@ -157,9 +157,9 @@ impl<C: HttpClient> Client<C> {
         password: &str,
         device_id: Option<&DeviceId>,
         initial_device_display_name: Option<&str>,
-    ) -> Result<login::v3::Response, Error<C::Error, ruma::api::client::Error>> {
+    ) -> Result<login::v3::Response, Error<C::Error, ruma::api::error::Error>> {
         let login_info = LoginInfo::Password(login::v3::Password::new(
-            UserIdentifier::UserIdOrLocalpart(user.to_owned()),
+            UserIdentifier::Matrix(MatrixUserIdentifier::new(user.to_owned())),
             password.to_owned(),
         ));
         let response = self
@@ -251,7 +251,7 @@ impl<C: HttpClient> Client<C> {
         set_presence: PresenceState,
         timeout: Option<Duration>,
     ) -> impl Stream<
-        Item = Result<sync_events::v3::Response, Error<C::Error, ruma::api::client::Error>>,
+        Item = Result<sync_events::v3::Response, Error<C::Error, ruma::api::error::Error>>,
     > + '_ {
         try_stream! {
             loop {
diff --git a/src/client/builder.rs b/src/client/builder.rs
index c69ec90..c2e8de6 100644
--- a/src/client/builder.rs
+++ b/src/client/builder.rs
@@ -60,7 +60,7 @@ impl ClientBuilder {
     /// Unless the supported Matrix versions were manually set via
     /// [`supported_matrix_versions`][Self::supported_matrix_versions], this will do a
     /// [`get_supported_versions`] request to find out about the supported versions.
-    pub async fn build<C>(self) -> Result<Client<C>, Error<C::Error, ruma::api::client::Error>>
+    pub async fn build<C>(self) -> Result<Client<C>, Error<C::Error, ruma::api::error::Error>>
     where
         C: DefaultConstructibleHttpClient,
     {
@@ -75,7 +75,7 @@ impl ClientBuilder {
     pub async fn http_client<C>(
         self,
         http_client: C,
-    ) -> Result<Client<C>, Error<C::Error, ruma::api::client::Error>>
+    ) -> Result<Client<C>, Error<C::Error, ruma::api::error::Error>>
     where
         C: HttpClient,
     {
diff --git a/src/error.rs b/src/error.rs
index 96d3242..d3e5fc9 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -2,7 +2,8 @@
 
 use std::fmt::{self, Debug, Display, Formatter};
 
-use ruma::api::error::{FromHttpResponseError, IntoHttpError};
+use as_variant::as_variant;
+use ruma::api::error::{FromHttpResponseError, FromHttpResponseErrorExt as _, IntoHttpError};
 
 /// An error that can occur during client operations.
 #[derive(Debug)]
@@ -24,14 +25,10 @@ pub enum Error<E, F> {
     FromHttpResponse(FromHttpResponseError<F>),
 }
 
-#[cfg(feature = "client-api")]
-impl<E> Error<E, ruma::api::client::Error> {
+impl<E> Error<E, ruma::api::error::Error> {
     /// If `self` is a server error in the `errcode` + `error` format expected
-    /// for client-server API endpoints, returns the error kind (`errcode`).
-    pub fn error_kind(&self) -> Option<&ruma::api::client::error::ErrorKind> {
-        use as_variant::as_variant;
-        use ruma::api::client::error::FromHttpResponseErrorExt as _;
-
+    /// for Matrix API endpoints, returns the error kind (`errcode`).
+    pub fn error_kind(&self) -> Option<&ruma::api::error::ErrorKind> {
         as_variant!(self, Self::FromHttpResponse)?.error_kind()
     }
 }