diff --git a/.gitignore b/.gitignore
index a480215..46a675e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
-zig-cache
+zig-cache/
+zig-out/
 doc/*.[1-9]
diff --git a/build.zig b/build.zig
index a913616..911f1f6 100644
--- a/build.zig
+++ b/build.zig
@@ -48,14 +48,12 @@ pub fn build(b: *zbs.Builder) !void {
 
     const examples = b.option(bool, "examples", "Set to true to build examples") orelse false;
 
-    // This logic must match std.build.resolveInstallPrefix()
-    const prefix = b.install_prefix orelse if (b.dest_dir) |_| "/usr" else b.cache_root;
-    const rel_config_path = if (mem.eql(u8, try fs.path.resolve(b.allocator, &[_][]const u8{prefix}), "/usr"))
+    const rel_config_path = if (mem.eql(u8, try fs.path.resolve(b.allocator, &[_][]const u8{b.install_prefix}), "/usr"))
         "../etc/river/init"
     else
         "etc/river/init";
     b.installFile("example/init", rel_config_path);
-    const abs_config_path = try fs.path.resolve(b.allocator, &[_][]const u8{ prefix, rel_config_path });
+    const abs_config_path = try fs.path.resolve(b.allocator, &[_][]const u8{ b.install_prefix, rel_config_path });
     assert(fs.path.isAbsolute(abs_config_path));
 
     const scanner = ScanProtocolsStep.create(b);
@@ -226,7 +224,7 @@ const ScdocStep = struct {
         for (scd_paths) |path| {
             const command = try std.fmt.allocPrint(
                 self.builder.allocator,
-                "scdoc < {} > {}",
+                "scdoc < {s} > {s}",
                 .{ path, path[0..(path.len - 4)] },
             );
             _ = try self.builder.exec(&[_][]const u8{ "sh", "-c", command });
@@ -243,7 +241,7 @@ const ScdocStep = struct {
 
             const output = try std.fmt.allocPrint(
                 self.builder.allocator,
-                "share/man/man{}/{}",
+                "share/man/man{s}/{s}",
                 .{ section, basename_no_ext },
             );
 
diff --git a/deps/zig-wayland b/deps/zig-wayland
index a453b26..a8e1efc 160000
--- a/deps/zig-wayland
+++ b/deps/zig-wayland
@@ -1 +1 @@
-Subproject commit a453b26a078b94b19ac5e0d40407e241fcd1b6af
+Subproject commit a8e1efcfd34ac798f19d8a62ebe3bb368c17f585
diff --git a/deps/zig-wlroots b/deps/zig-wlroots
index 6c62568..d6444e7 160000
--- a/deps/zig-wlroots
+++ b/deps/zig-wlroots
@@ -1 +1 @@
-Subproject commit 6c62568adfe92a1852566b7d091e99f4b28cbabb
+Subproject commit d6444e7a8d43750e2d4ce0cb76483ff968848cb1
diff --git a/deps/zig-xkbcommon b/deps/zig-xkbcommon
index 9e4d41f..10cdca6 160000
--- a/deps/zig-xkbcommon
+++ b/deps/zig-xkbcommon
@@ -1 +1 @@
-Subproject commit 9e4d41fe9414094db31c873c2ad9cadcd8999cf6
+Subproject commit 10cdca686dacb91d6cfe37f1839b6aedfb53cc4c
diff --git a/river/Config.zig b/river/Config.zig
index fe95d6b..9a4c75f 100644
--- a/river/Config.zig
+++ b/river/Config.zig
@@ -112,8 +112,8 @@ pub fn init() !Self {
 }
 
 pub fn deinit(self: *Self) void {
-    var it = self.mode_to_id.iterator();
-    while (it.next()) |e| util.gpa.free(e.key);
+    var it = self.mode_to_id.keyIterator();
+    while (it.next()) |key| util.gpa.free(key.*);
     self.mode_to_id.deinit();
 
     for (self.modes.items) |mode| mode.deinit();
diff --git a/river/Control.zig b/river/Control.zig
index 73ca0f1..ff7ca3f 100644
--- a/river/Control.zig
+++ b/river/Control.zig
@@ -77,8 +77,8 @@ fn handleRequest(control: *zriver.ControlV1, request: zriver.ControlV1.Request,
                 return;
             };
 
-            const entry = self.args_map.getEntry(.{ .client = control.getClient(), .id = control.getId() }).?;
-            entry.value.append(util.gpa, owned_slice) catch {
+            const args = self.args_map.getPtr(.{ .client = control.getClient(), .id = control.getId() }).?;
+            args.append(util.gpa, owned_slice) catch {
                 control.getClient().postNoMemory();
                 util.gpa.free(owned_slice);
                 return;
@@ -96,16 +96,15 @@ fn handleRequest(control: *zriver.ControlV1, request: zriver.ControlV1.Request,
                 return;
             };
 
-            const entry = self.args_map.getEntry(.{ .client = control.getClient(), .id = control.getId() }).?;
+            const args = self.args_map.getPtr(.{ .client = control.getClient(), .id = control.getId() }).?;
             defer {
-                for (entry.value.items) |arg| util.gpa.free(arg);
-                entry.value.items.len = 0;
+                for (args.items) |arg| util.gpa.free(arg);
+                args.items.len = 0;
             }
-            const args = entry.value.items;
 
             var out: ?[]const u8 = null;
             defer if (out) |s| util.gpa.free(s);
-            command.run(util.gpa, seat, args, &out) catch |err| {
+            command.run(util.gpa, seat, args.items, &out) catch |err| {
                 const failure_message = switch (err) {
                     command.Error.OutOfMemory => {
                         callback.getClient().postNoMemory();
@@ -137,9 +136,9 @@ fn handleRequest(control: *zriver.ControlV1, request: zriver.ControlV1.Request,
 
 /// Remove the resource from the hash map and free all stored args
 fn handleDestroy(control: *zriver.ControlV1, self: *Self) void {
-    var list = self.args_map.remove(
+    var args = self.args_map.fetchRemove(
         .{ .client = control.getClient(), .id = control.getId() },
     ).?.value;
-    for (list.items) |arg| util.gpa.free(arg);
-    list.deinit(util.gpa);
+    for (args.items) |arg| util.gpa.free(arg);
+    args.deinit(util.gpa);
 }
diff --git a/river/Cursor.zig b/river/Cursor.zig
index 0884009..fa65849 100644
--- a/river/Cursor.zig
+++ b/river/Cursor.zig
@@ -149,7 +149,7 @@ pub fn setTheme(self: *Self, theme: ?[*:0]const u8, _size: ?u32) !void {
     while (it) |node| : (it = node.next) {
         const wlr_output = node.data.wlr_output;
         self.xcursor_manager.load(wlr_output.scale) catch
-            log.err("failed to load xcursor theme '{}' at scale {}", .{ theme, wlr_output.scale });
+            log.err("failed to load xcursor theme '{s}' at scale {}", .{ theme, wlr_output.scale });
     }
 
     // If this cursor belongs to the default seat, set the xcursor environment
@@ -162,7 +162,7 @@ pub fn setTheme(self: *Self, theme: ?[*:0]const u8, _size: ?u32) !void {
 
         if (build_options.xwayland) {
             self.xcursor_manager.load(1) catch {
-                log.err("failed to load xcursor theme '{}' at scale 1", .{theme});
+                log.err("failed to load xcursor theme '{s}' at scale 1", .{theme});
                 return;
             };
             const wlr_xcursor = self.xcursor_manager.getXcursor("left_ptr", 1).?;
@@ -525,8 +525,8 @@ fn surfaceAtFilter(view: *View, filter_tags: u32) bool {
 }
 
 /// Enter move or resize mode
-pub fn enterMode(self: *Self, mode: @TagType(Mode), view: *View) void {
-    log.debug("enter {} mode", .{@tagName(mode)});
+pub fn enterMode(self: *Self, mode: std.meta.Tag((Mode)), view: *View) void {
+    log.debug("enter {s} mode", .{@tagName(mode)});
 
     self.seat.focus(view);
 
@@ -575,7 +575,7 @@ pub fn enterMode(self: *Self, mode: @TagType(Mode), view: *View) void {
 fn leaveMode(self: *Self, event: *wlr.Pointer.event.Button) void {
     std.debug.assert(self.mode != .passthrough);
 
-    log.debug("leave {} mode", .{@tagName(self.mode)});
+    log.debug("leave {s} mode", .{@tagName(self.mode)});
 
     // If we were in down mode, we need pass along the release event
     if (self.mode == .down)
diff --git a/river/LayerSurface.zig b/river/LayerSurface.zig
index 6c165dd..2968895 100644
--- a/river/LayerSurface.zig
+++ b/river/LayerSurface.zig
@@ -74,7 +74,7 @@ pub fn init(self: *Self, output: *Output, wlr_layer_surface: *wlr.LayerSurfaceV1
 fn handleDestroy(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wlr.LayerSurfaceV1) void {
     const self = @fieldParentPtr(Self, "destroy", listener);
 
-    log.debug("layer surface '{}' destroyed", .{self.wlr_layer_surface.namespace});
+    log.debug("layer surface '{s}' destroyed", .{self.wlr_layer_surface.namespace});
 
     // Remove listeners active the entire lifetime of the layer surface
     self.destroy.link.remove();
@@ -90,7 +90,7 @@ fn handleDestroy(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface:
 fn handleMap(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wlr.LayerSurfaceV1) void {
     const self = @fieldParentPtr(Self, "map", listener);
 
-    log.debug("layer surface '{}' mapped", .{wlr_layer_surface.namespace});
+    log.debug("layer surface '{s}' mapped", .{wlr_layer_surface.namespace});
 
     // Add listeners that are only active while mapped
     wlr_layer_surface.surface.events.commit.add(&self.commit);
@@ -104,7 +104,7 @@ fn handleMap(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wl
 fn handleUnmap(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wlr.LayerSurfaceV1) void {
     const self = @fieldParentPtr(Self, "unmap", listener);
 
-    log.debug("layer surface '{}' unmapped", .{self.wlr_layer_surface.namespace});
+    log.debug("layer surface '{s}' unmapped", .{self.wlr_layer_surface.namespace});
 
     // remove listeners only active while the layer surface is mapped
     self.commit.link.remove();
diff --git a/river/Layout.zig b/river/Layout.zig
index b5c72a9..9b607ac 100644
--- a/river/Layout.zig
+++ b/river/Layout.zig
@@ -99,8 +99,8 @@ fn handleRequestInert(layout: *river.LayoutV2, request: river.LayoutV2.Request,
 /// Send a layout demand to the client
 pub fn startLayoutDemand(self: *Self, views: u32) void {
     log.debug(
-        "starting layout demand '{}' on output '{}'",
-        .{ self.namespace, self.output.wlr_output.name },
+        "starting layout demand '{s}' on output '{s}'",
+        .{ self.namespace, mem.sliceTo(&self.output.wlr_output.name, 0) },
     );
 
     std.debug.assert(self.output.layout_demand == null);
@@ -137,8 +137,8 @@ fn handleRequest(layout: *river.LayoutV2, request: river.LayoutV2.Request, self:
         // to the layout demand matching the serial.
         .push_view_dimensions => |req| {
             log.debug(
-                "layout '{}' on output '{}' pushed view dimensions: {} {} {} {}",
-                .{ self.namespace, self.output.wlr_output.name, req.x, req.y, req.width, req.height },
+                "layout '{s}' on output '{s}' pushed view dimensions: {} {} {} {}",
+                .{ self.namespace, mem.sliceTo(&self.output.wlr_output.name, 0), req.x, req.y, req.width, req.height },
             );
 
             if (self.output.layout_demand) |*layout_demand| {
@@ -154,8 +154,8 @@ fn handleRequest(layout: *river.LayoutV2, request: river.LayoutV2.Request, self:
         // of the layout demand matching the serial as done.
         .commit => |req| {
             log.debug(
-                "layout '{}' on output '{}' commited",
-                .{ self.namespace, self.output.wlr_output.name },
+                "layout '{s}' on output '{s}' commited",
+                .{ self.namespace, mem.sliceTo(&self.output.wlr_output.name, 0) },
             );
 
             if (self.output.layout_demand) |*layout_demand| {
@@ -170,8 +170,8 @@ fn handleRequest(layout: *river.LayoutV2, request: river.LayoutV2.Request, self:
 
 fn handleDestroy(layout: *river.LayoutV2, self: *Self) void {
     log.debug(
-        "destroying layout '{}' on output '{}'",
-        .{ self.namespace, self.output.wlr_output.name },
+        "destroying layout '{s}' on output '{s}'",
+        .{ self.namespace, mem.sliceTo(&self.output.wlr_output.name, 0) },
     );
 
     // Remove layout from the list
diff --git a/river/LayoutDemand.zig b/river/LayoutDemand.zig
index 12c58c1..41f4a94 100644
--- a/river/LayoutDemand.zig
+++ b/river/LayoutDemand.zig
@@ -18,6 +18,7 @@
 const Self = @This();
 
 const std = @import("std");
+const mem = std.mem;
 const wlr = @import("wlroots");
 const wayland = @import("wayland");
 const wl = wayland.server.wl;
@@ -69,8 +70,8 @@ pub fn deinit(self: *const Self) void {
 /// All further responses to the event will simply be ignored.
 fn handleTimeout(layout: *Layout) callconv(.C) c_int {
     log.notice(
-        "layout demand for layout '{}' on output '{}' timed out",
-        .{ layout.namespace, layout.output.wlr_output.name },
+        "layout demand for layout '{s}' on output '{s}' timed out",
+        .{ layout.namespace, mem.sliceTo(&layout.output.wlr_output.name, 0) },
     );
     layout.output.layout_demand.?.deinit();
     layout.output.layout_demand = null;
diff --git a/river/LayoutManager.zig b/river/LayoutManager.zig
index 5e17eae..98df1c7 100644
--- a/river/LayoutManager.zig
+++ b/river/LayoutManager.zig
@@ -67,7 +67,7 @@ fn handleRequest(layout_manager: *river.LayoutManagerV2, request: river.LayoutMa
             const wlr_output = wlr.Output.fromWlOutput(req.output) orelse return;
             const output = @intToPtr(*Output, wlr_output.data);
 
-            log.debug("bind layout '{}' on output '{}'", .{ req.namespace, output.wlr_output.name });
+            log.debug("bind layout '{s}' on output '{s}'", .{ req.namespace, mem.sliceTo(&output.wlr_output.name, 0) });
 
             Layout.create(
                 layout_manager.getClient(),
diff --git a/river/Output.zig b/river/Output.zig
index 0c8bc1d..4bd1bb2 100644
--- a/river/Output.zig
+++ b/river/Output.zig
@@ -304,7 +304,7 @@ fn arrangeLayer(
             // should only ever be encountered very rarely and matches the
             // behavior of other compositors.
             std.log.scoped(.layer_shell).warn(
-                "margins of layer surface '{}' are too large to be reasonably handled. Closing.",
+                "margins of layer surface '{s}' are too large to be reasonably handled. Closing.",
                 .{layer_surface.wlr_layer_surface.namespace},
             );
             layer_surface.wlr_layer_surface.close();
@@ -333,7 +333,7 @@ fn arrangeLayer(
         if (vertical_margin_size >= bounds.height) {
             // TODO find a better solution, see explanation above
             std.log.scoped(.layer_shell).warn(
-                "margins of layer surface '{}' are too large to be reasonably handled. Closing.",
+                "margins of layer surface '{s}' are too large to be reasonably handled. Closing.",
                 .{layer_surface.wlr_layer_surface.namespace},
             );
             layer_surface.wlr_layer_surface.close();
@@ -419,7 +419,7 @@ fn arrangeLayer(
 fn handleDestroy(listener: *wl.Listener(*wlr.Output), wlr_output: *wlr.Output) void {
     const self = @fieldParentPtr(Self, "destroy", listener);
 
-    std.log.scoped(.server).debug("output '{}' destroyed", .{self.wlr_output.name});
+    std.log.scoped(.server).debug("output '{s}' destroyed", .{mem.sliceTo(&self.wlr_output.name, 0)});
 
     // Remove the destroyed output from root if it wasn't already removed
     server.root.removeOutput(self);
@@ -482,7 +482,7 @@ pub fn getEffectiveResolution(self: *Self) struct { width: u32, height: u32 } {
 
 fn setTitle(self: Self) void {
     var buf: ["river - ".len + self.wlr_output.name.len + 1]u8 = undefined;
-    const title = fmt.bufPrintZ(&buf, "river - {}", .{mem.spanZ(&self.wlr_output.name)}) catch unreachable;
+    const title = fmt.bufPrintZ(&buf, "river - {s}", .{mem.sliceTo(&self.wlr_output.name, 0)}) catch unreachable;
     if (self.wlr_output.isWl()) {
         self.wlr_output.wlSetTitle(title);
     } else if (wlr.config.has_x11_backend and self.wlr_output.isX11()) {
diff --git a/river/Root.zig b/river/Root.zig
index d0cc268..10adb66 100644
--- a/river/Root.zig
+++ b/river/Root.zig
@@ -19,6 +19,7 @@ const Self = @This();
 
 const build_options = @import("build_options");
 const std = @import("std");
+const mem = std.mem;
 const assert = std.debug.assert;
 const wlr = @import("wlroots");
 const wl = @import("wayland").server.wl;
@@ -75,7 +76,7 @@ xwayland_unmanaged_views: if (build_options.xwayland)
     std.TailQueue(XwaylandUnmanaged)
 else
     void = if (build_options.xwayland)
-    .{},
+.{},
 
 /// Number of layout demands pending before the transaction may be started.
 pending_layout_demands: u32 = 0,
@@ -128,7 +129,7 @@ pub fn deinit(self: *Self) void {
 
 fn handleNewOutput(listener: *wl.Listener(*wlr.Output), wlr_output: *wlr.Output) void {
     const self = @fieldParentPtr(Self, "new_output", listener);
-    std.log.scoped(.output_manager).debug("new output {}", .{wlr_output.name});
+    std.log.scoped(.output_manager).debug("new output {s}", .{mem.sliceTo(&wlr_output.name, 0)});
 
     const node = util.gpa.create(std.TailQueue(Output).Node) catch {
         wlr_output.destroy();
@@ -475,7 +476,7 @@ fn applyOutputConfig(self: *Self, config: *wlr.OutputConfigurationV1) bool {
         // Since we have done a successful test commit, this will only fail
         // due to error in the output's backend implementation.
         output.wlr_output.commit() catch
-            std.log.scoped(.output_manager).err("output commit failed for {}", .{output.wlr_output.name});
+            std.log.scoped(.output_manager).err("output commit failed for {s}", .{mem.sliceTo(&output.wlr_output.name, 0)});
 
         if (output.wlr_output.enabled) {
             // Moves the output if it is already in the layout
@@ -514,8 +515,8 @@ fn testOutputConfig(config: *wlr.OutputConfigurationV1, rollback: bool) bool {
 
         if (too_small) {
             std.log.scoped(.output_manager).info(
-                "The requested output resolution {}x{} scaled with {} for {} would be too small.",
-                .{ width, height, scale, wlr_output.name },
+                "The requested output resolution {}x{} scaled with {} for {s} would be too small.",
+                .{ width, height, scale, mem.sliceTo(&wlr_output.name, 0) },
             );
         }
 
@@ -586,11 +587,12 @@ fn handlePowerManagerSetMode(
 
     const log_text = if (enable) "Enabling" else "Disabling";
     std.log.scoped(.output_manager).debug(
-        "{} dpms for output {}",
-        .{ log_text, event.output.name },
+        "{s} dpms for output {s}",
+        .{ log_text, mem.sliceTo(&event.output.name, 0) },
     );
 
     event.output.enable(enable);
-    event.output.commit() catch
-        std.log.scoped(.server).err("output commit failed for {}", .{event.output.name});
+    event.output.commit() catch {
+        std.log.scoped(.server).err("output commit failed for {s}", .{mem.sliceTo(&event.output.name, 0)});
+    };
 }
diff --git a/river/Seat.zig b/river/Seat.zig
index d47d64c..57ccef5 100644
--- a/river/Seat.zig
+++ b/river/Seat.zig
@@ -319,13 +319,14 @@ pub fn handleMapping(
                     command.Error.Other => out.?,
                     else => command.errToMsg(err),
                 };
-                std.log.scoped(.command).err("{}: {}", .{ args[0], failure_message });
+                std.log.scoped(.command).err("{s}: {s}", .{ args[0], failure_message });
                 return true;
             };
             if (out) |s| {
-                const stdout = std.io.getStdOut().outStream();
-                stdout.print("{}", .{s}) catch
-                |err| std.log.scoped(.command).err("{}: write to stdout failed {}", .{ args[0], err });
+                const stdout = std.io.getStdOut().writer();
+                stdout.print("{s}", .{s}) catch |err| {
+                    std.log.scoped(.command).err("{s}: write to stdout failed {}", .{ args[0], err });
+                };
             }
             return true;
         }
diff --git a/river/Server.zig b/river/Server.zig
index 0f059e0..6d9a861 100644
--- a/river/Server.zig
+++ b/river/Server.zig
@@ -19,6 +19,7 @@ const Self = @This();
 
 const build_options = @import("build_options");
 const std = @import("std");
+const mem = std.mem;
 const wlr = @import("wlroots");
 const wl = @import("wayland").server.wl;
 
@@ -188,7 +189,7 @@ fn handleNewLayerSurface(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_
     const self = @fieldParentPtr(Self, "new_layer_surface", listener);
 
     log.debug(
-        "New layer surface: namespace {}, layer {}, anchor {}, size {}x{}, margin ({},{},{},{}), exclusive_zone {}",
+        "New layer surface: namespace {s}, layer {}, anchor {}, size {}x{}, margin ({},{},{},{}), exclusive_zone {}",
         .{
             wlr_layer_surface.namespace,
             wlr_layer_surface.client_pending.layer,
@@ -208,13 +209,13 @@ fn handleNewLayerSurface(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_
     if (wlr_layer_surface.output == null) {
         const output = self.input_manager.defaultSeat().focused_output;
         if (output == &self.root.noop_output) {
-            log.err("no output available for layer surface '{}'", .{wlr_layer_surface.namespace});
+            log.err("no output available for layer surface '{s}'", .{wlr_layer_surface.namespace});
             wlr_layer_surface.close();
             return;
         }
 
-        log.debug("new layer surface had null output, assigning it to output '{}'", .{
-            output.wlr_output.name,
+        log.debug("new layer surface had null output, assigning it to output '{s}'", .{
+            mem.sliceTo(&output.wlr_output.name, 0),
         });
         wlr_layer_surface.output = output.wlr_output;
     }
@@ -241,7 +242,7 @@ fn handleNewXwaylandSurface(listener: *wl.Listener(*wlr.XwaylandSurface), wlr_xw
     }
 
     log.debug(
-        "new xwayland surface: title '{}', class '{}'",
+        "new xwayland surface: title '{s}', class '{s}'",
         .{ wlr_xwayland_surface.title, wlr_xwayland_surface.class },
     );
 
diff --git a/river/View.zig b/river/View.zig
index 2287e28..3c6f4f2 100644
--- a/river/View.zig
+++ b/river/View.zig
@@ -446,7 +446,7 @@ pub fn shouldTrackConfigure(self: Self) bool {
 pub fn map(self: *Self) void {
     self.pending.target_opacity = server.config.opacity.unfocused;
 
-    log.debug("view '{}' mapped", .{self.getTitle()});
+    log.debug("view '{s}' mapped", .{self.getTitle()});
 
     if (self.foreign_toplevel_handle == null) {
         self.foreign_toplevel_handle = wlr.ForeignToplevelHandleV1.create(
@@ -487,7 +487,7 @@ pub fn map(self: *Self) void {
 
 /// Called by the impl when the surface will no longer be displayed
 pub fn unmap(self: *Self) void {
-    log.debug("view '{}' unmapped", .{self.getTitle()});
+    log.debug("view '{s}' unmapped", .{self.getTitle()});
 
     self.destroying = true;
     if (self.saved_buffers.items.len == 0) self.saveBuffers();
@@ -558,7 +558,7 @@ fn killOpacityTimer(self: *Self) void {
 fn armOpacityTimer(self: *Self) void {
     const delta_t = server.config.opacity.delta_t;
     self.opacity_timer.?.timerUpdate(delta_t) catch |err| {
-        log.err("failed to update opacity timer: {}", .{err});
+        log.err("failed to update opacity timer: {s}", .{err});
         self.killOpacityTimer();
     };
 }
@@ -577,7 +577,7 @@ fn handleOpacityTimer(self: *Self) callconv(.C) c_int {
 fn attachOpacityTimer(self: *Self) void {
     const event_loop = server.wl_server.getEventLoop();
     self.opacity_timer = event_loop.addTimer(*Self, handleOpacityTimer, self) catch {
-        log.err("failed to create opacity timer for view '{}'", .{self.getTitle()});
+        log.err("failed to create opacity timer for view '{s}'", .{self.getTitle()});
         return;
     };
     self.armOpacityTimer();
diff --git a/river/command/enter_mode.zig b/river/command/enter_mode.zig
index 1fcd81f..fe279f2 100644
--- a/river/command/enter_mode.zig
+++ b/river/command/enter_mode.zig
@@ -45,7 +45,7 @@ pub fn enterMode(
     const mode_id = server.config.mode_to_id.get(target_mode) orelse {
         out.* = try std.fmt.allocPrint(
             allocator,
-            "cannot enter non-existant mode '{}'",
+            "cannot enter non-existant mode '{s}'",
             .{target_mode},
         );
         return Error.Other;
diff --git a/river/command/map.zig b/river/command/map.zig
index eddf7af..ab8a53a 100644
--- a/river/command/map.zig
+++ b/river/command/map.zig
@@ -85,7 +85,7 @@ pub fn mapPointer(
     else {
         out.* = try std.fmt.allocPrint(
             allocator,
-            "invalid pointer action {}, must be move-view or resize-view",
+            "invalid pointer action {s}, must be move-view or resize-view",
             .{args[4]},
         );
         return Error.Other;
@@ -110,7 +110,7 @@ fn modeNameToId(allocator: *std.mem.Allocator, seat: *Seat, mode_name: []const u
     return config.mode_to_id.get(mode_name) orelse {
         out.* = try std.fmt.allocPrint(
             allocator,
-            "cannot add/remove mapping to/from non-existant mode '{}'",
+            "cannot add/remove mapping to/from non-existant mode '{s}'",
             .{mode_name},
         );
         return Error.Other;
@@ -153,7 +153,7 @@ fn parseEventCode(allocator: *std.mem.Allocator, event_code_str: []const u8, out
     defer allocator.free(event_code_name);
     const ret = c.libevdev_event_code_from_name(c.EV_KEY, event_code_name);
     if (ret < 1) {
-        out.* = try std.fmt.allocPrint(allocator, "unknown button {}", .{event_code_str});
+        out.* = try std.fmt.allocPrint(allocator, "unknown button {s}", .{event_code_str});
         return Error.Other;
     }
 
@@ -165,7 +165,7 @@ fn parseKeysym(allocator: *std.mem.Allocator, keysym_str: []const u8, out: *?[]c
     defer allocator.free(keysym_name);
     const keysym = xkb.Keysym.fromName(keysym_name, .case_insensitive);
     if (keysym == .NoSymbol) {
-        out.* = try std.fmt.allocPrint(allocator, "invalid keysym '{}'", .{keysym_str});
+        out.* = try std.fmt.allocPrint(allocator, "invalid keysym '{s}'", .{keysym_str});
         return Error.Other;
     }
     return keysym;
@@ -195,11 +195,7 @@ fn parseModifiers(
                 continue :outer;
             }
         }
-        out.* = try std.fmt.allocPrint(
-            allocator,
-            "invalid modifier '{}'",
-            .{mod_name},
-        );
+        out.* = try std.fmt.allocPrint(allocator, "invalid modifier '{s}'", .{mod_name});
         return Error.Other;
     }
     return modifiers;
diff --git a/river/main.zig b/river/main.zig
index ce8c4dd..874b518 100644
--- a/river/main.zig
+++ b/river/main.zig
@@ -52,7 +52,7 @@ pub fn main() anyerror!void {
         _ = it.nextPosix();
         while (it.nextPosix()) |arg| {
             if (std.mem.eql(u8, arg, "-h")) {
-                const stdout = std.io.getStdOut().outStream();
+                const stdout = std.io.getStdOut().writer();
                 try stdout.print(usage, .{});
                 os.exit(0);
             } else if (std.mem.eql(u8, arg, "-c")) {
@@ -67,13 +67,13 @@ pub fn main() anyerror!void {
             } else if (std.mem.eql(u8, arg, "-l")) {
                 if (it.nextPosix()) |level_str| {
                     const log_level = std.fmt.parseInt(u3, level_str, 10) catch
-                        printErrorExit("Error: invalid log level '{}'", .{level_str});
+                        printErrorExit("Error: invalid log level '{s}'", .{level_str});
                     level = @intToEnum(std.log.Level, log_level);
                 } else {
                     printErrorExit("Error: flag '-l' requires exactly one argument", .{});
                 }
             } else {
-                const stderr = std.io.getStdErr().outStream();
+                const stderr = std.io.getStdErr().writer();
                 try stderr.print(usage, .{});
                 os.exit(1);
             }
@@ -99,7 +99,7 @@ pub fn main() anyerror!void {
     // Run the child in a new process group so that we can send SIGTERM to all
     // descendants on exit.
     const child_pgid = if (startup_command) |cmd| blk: {
-        std.log.info("running startup command '{}'", .{cmd});
+        std.log.info("running startup command '{s}'", .{cmd});
         const child_args = [_:null]?[*:0]const u8{ "/bin/sh", "-c", cmd, null };
         const pid = try os.fork();
         if (pid == 0) {
@@ -112,7 +112,7 @@ pub fn main() anyerror!void {
         break :blk pid;
     } else null;
     defer if (child_pgid) |pgid|
-        os.kill(-pgid, os.SIGTERM) catch |e| std.log.err("failed to kill startup process: {}", .{e});
+        os.kill(-pgid, os.SIGTERM) catch |e| std.log.err("failed to kill startup process: {s}", .{e});
 
     std.log.info("running server", .{});
 
@@ -122,7 +122,7 @@ pub fn main() anyerror!void {
 }
 
 fn printErrorExit(comptime format: []const u8, args: anytype) noreturn {
-    const stderr = std.io.getStdErr().outStream();
+    const stderr = std.io.getStdErr().writer();
     stderr.print(format ++ "\n", args) catch os.exit(1);
     os.exit(1);
 }
@@ -138,11 +138,11 @@ fn testConfigPath(comptime fmt: []const u8, args: anytype) std.fmt.AllocPrintErr
 
 fn getStartupCommand() std.fmt.AllocPrintError!?[:0]const u8 {
     if (os.getenv("XDG_CONFIG_HOME")) |xdg_config_home| {
-        if (try testConfigPath("{}/river/init", .{xdg_config_home})) |path| {
+        if (try testConfigPath("{s}/river/init", .{xdg_config_home})) |path| {
             return path;
         }
     } else if (os.getenv("HOME")) |home| {
-        if (try testConfigPath("{}/.config/river/init", .{home})) |path| {
+        if (try testConfigPath("{s}/.config/river/init", .{home})) |path| {
             return path;
         }
     }
diff --git a/river/render.zig b/river/render.zig
index c1157b9..a0275c9 100644
--- a/river/render.zig
+++ b/river/render.zig
@@ -17,6 +17,7 @@
 
 const build_options = @import("build_options");
 const std = @import("std");
+const mem = std.mem;
 const os = std.os;
 const wlr = @import("wlroots");
 const wl = @import("wayland").server.wl;
@@ -159,7 +160,7 @@ pub fn renderOutput(output: *Output) void {
 
     // TODO: handle failure
     output.wlr_output.commit() catch
-        log.err("output commit failed for {}", .{output.wlr_output.name});
+        log.err("output commit failed for {s}", .{mem.sliceTo(&output.wlr_output.name, 0)});
 }
 
 fn renderFilter(view: *View, filter_tags: u32) bool {
diff --git a/riverctl/main.zig b/riverctl/main.zig
index 8837f79..9d4c8b6 100644
--- a/riverctl/main.zig
+++ b/riverctl/main.zig
@@ -92,17 +92,17 @@ fn callbackListener(callback: *zriver.CommandCallbackV1, event: zriver.CommandCa
     switch (event) {
         .success => |success| {
             if (mem.len(success.output) > 0) {
-                const stdout = std.io.getStdOut().outStream();
-                stdout.print("{}\n", .{success.output}) catch @panic("failed to write to stdout");
+                const stdout = std.io.getStdOut().writer();
+                stdout.print("{s}\n", .{success.output}) catch @panic("failed to write to stdout");
             }
             os.exit(0);
         },
-        .failure => |failure| printErrorExit("Error: {}\n", .{failure.failure_message}),
+        .failure => |failure| printErrorExit("Error: {s}\n", .{failure.failure_message}),
     }
 }
 
 pub fn printErrorExit(comptime format: []const u8, args: anytype) noreturn {
-    const stderr = std.io.getStdErr().outStream();
+    const stderr = std.io.getStdErr().writer();
     stderr.print("err: " ++ format ++ "\n", args) catch std.os.exit(1);
     std.os.exit(1);
 }