diff --git a/Cargo.toml b/Cargo.toml
index 434429ff..81a25442 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas"
-version = "0.14.3"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -132,14 +132,14 @@ recursive-layout-widgets = ["kas-core/recursive-layout-widgets"]
 unsafe_node = ["kas-core/unsafe_node"]
 
 [dependencies]
-kas-core = { version = "0.14.1", path = "crates/kas-core" }
-kas-dylib = { version = "0.14.2", path = "crates/kas-dylib", optional = true }
-kas-widgets = { version = "0.14.2", path = "crates/kas-widgets" }
-kas-view = { version = "0.14.2", path = "crates/kas-view", optional = true }
-kas-resvg = { version = "0.14.2", path = "crates/kas-resvg", optional = true }
+kas-core = { version = "0.15.0", path = "crates/kas-core" }
+kas-dylib = { version = "0.15.0", path = "crates/kas-dylib", optional = true }
+kas-widgets = { version = "0.15.0", path = "crates/kas-widgets" }
+kas-view = { version = "0.15.0", path = "crates/kas-view", optional = true }
+kas-resvg = { version = "0.15.0", path = "crates/kas-resvg", optional = true }
 
 [dependencies.kas-wgpu]
-version = "0.14.2"
+version = "0.15.0"
 path = "crates/kas-wgpu"
 optional = true
 default-features = false
diff --git a/ROADMAP.md b/ROADMAP.md
index 9a12e3dc..41f7b0fd 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -170,6 +170,11 @@ to event handlers and to a new `update` method. The key advantages of this chang
 
 For more on *input data*, read the [design document](https://github.com/kas-gui/design/blob/input-data/widget/input-data.md).
 
+### 0.15.0 — December 2024
+
+Add traits `Collection` and `CellCollection` representing a list/tuple of widgets.
+Revise layout macros with `.align` / `.pack` / `.margins` adapters.
+
 
 Future work
 -----------
diff --git a/crates/kas-core/Cargo.toml b/crates/kas-core/Cargo.toml
index 4e710597..6ae3dae7 100644
--- a/crates/kas-core/Cargo.toml
+++ b/crates/kas-core/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-core"
-version = "0.14.1"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -119,7 +119,7 @@ arboard = { version = "3.2.0", optional = true, default-features = false }
 
 
 [dependencies.kas-macros]
-version = "0.14.1"
+version = "0.15.0"
 path = "../kas-macros"
 
 [dependencies.kas-text]
diff --git a/crates/kas-dylib/Cargo.toml b/crates/kas-dylib/Cargo.toml
index e8911938..e876e388 100644
--- a/crates/kas-dylib/Cargo.toml
+++ b/crates/kas-dylib/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-dylib"
-version = "0.14.2"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -27,7 +27,7 @@ resvg = ["dep:kas-resvg"]
 docs_rs = ["kas-core/winit", "kas-core/wayland"]
 
 [dependencies]
-kas-core = { version = "0.14.1", path = "../kas-core" }
-kas-widgets = { version = "0.14.2", path = "../kas-widgets" }
-kas-resvg = { version = "0.14.2", path = "../kas-resvg", optional = true }
-kas-wgpu = { version = "0.14.1", path = "../kas-wgpu", default-features = false }
+kas-core = { version = "0.15.0", path = "../kas-core" }
+kas-widgets = { version = "0.15.0", path = "../kas-widgets" }
+kas-resvg = { version = "0.15.0", path = "../kas-resvg", optional = true }
+kas-wgpu = { version = "0.15.0", path = "../kas-wgpu", default-features = false }
diff --git a/crates/kas-macros/Cargo.toml b/crates/kas-macros/Cargo.toml
index 1a4314e4..210edfed 100644
--- a/crates/kas-macros/Cargo.toml
+++ b/crates/kas-macros/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-macros"
-version = "0.14.1"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
diff --git a/crates/kas-resvg/Cargo.toml b/crates/kas-resvg/Cargo.toml
index 816cf638..9820cb14 100644
--- a/crates/kas-resvg/Cargo.toml
+++ b/crates/kas-resvg/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-resvg"
-version = "0.14.2"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -33,7 +33,7 @@ thiserror = "2.0.3"
 
 [dependencies.kas]
 # We must rename this package since macros expect kas to be in scope:
-version = "0.14.1"
+version = "0.15.0"
 package = "kas-core"
 path = "../kas-core"
 features = ["spawn"]
diff --git a/crates/kas-view/Cargo.toml b/crates/kas-view/Cargo.toml
index 785b70f7..d2c79b8b 100644
--- a/crates/kas-view/Cargo.toml
+++ b/crates/kas-view/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-view"
-version = "0.14.2"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -17,12 +17,12 @@ features = ["kas/winit", "kas/wayland"]
 rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
-kas-widgets = { version = "0.14.1", path = "../kas-widgets" }
+kas-widgets = { version = "0.15.0", path = "../kas-widgets" }
 log = "0.4"
 linear-map = "1.2.0"
 
 # We must rename this package since macros expect kas to be in scope:
-kas = { version = "0.14.1", package = "kas-core", path = "../kas-core" }
+kas = { version = "0.15.0", package = "kas-core", path = "../kas-core" }
 
 [lints.clippy]
 collapsible_else_if = "allow"
diff --git a/crates/kas-wgpu/Cargo.toml b/crates/kas-wgpu/Cargo.toml
index 99e19191..a8394e64 100644
--- a/crates/kas-wgpu/Cargo.toml
+++ b/crates/kas-wgpu/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-wgpu"
-version = "0.14.2"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -39,7 +39,7 @@ rustc-hash = "2.0"
 
 [dependencies.kas]
 # Rename package purely for convenience:
-version = "0.14.1"
+version = "0.15.0"
 package = "kas-core"
 path = "../kas-core"
 
diff --git a/crates/kas-widgets/Cargo.toml b/crates/kas-widgets/Cargo.toml
index 3844b794..c900af59 100644
--- a/crates/kas-widgets/Cargo.toml
+++ b/crates/kas-widgets/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-widgets"
-version = "0.14.2"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -26,11 +26,11 @@ smallvec = "1.6.1"
 unicode-segmentation = "1.7"
 thiserror = "2.0.3"
 image = { version = "0.25.1", optional = true }
-kas-macros = { version = "0.14.1", path = "../kas-macros" }
+kas-macros = { version = "0.15.0", path = "../kas-macros" }
 linear-map = "1.2.0"
 
 # We must rename this package since macros expect kas to be in scope:
-kas = { version = "0.14.1", package = "kas-core", path = "../kas-core" }
+kas = { version = "0.15.0", package = "kas-core", path = "../kas-core" }
 
 [lints.clippy]
 collapsible_else_if = "allow"
diff --git a/examples/mandlebrot/Cargo.toml b/examples/mandlebrot/Cargo.toml
index a54fc3ca..d5ef408a 100644
--- a/examples/mandlebrot/Cargo.toml
+++ b/examples/mandlebrot/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "kas-mandlebrot"
-version = "0.14.1"
+version = "0.15.0"
 authors = ["Diggory Hardy <git@dhardy.name>"]
 edition = "2021"
 license = "Apache-2.0"
@@ -8,8 +8,8 @@ description = "KAS GUI / Mandlebrot example"
 publish = false
 
 [dependencies]
-kas = { version = "0.14.1", features = ["wgpu"], path = "../.." }
-kas-wgpu = { version = "0.14.1", path = "../../crates/kas-wgpu" }
+kas = { version = "0.15.0", features = ["wgpu"], path = "../.." }
+kas-wgpu = { version = "0.15.0", path = "../../crates/kas-wgpu" }
 chrono = "0.4"
 env_logger = "0.11"
 log = "0.4"