diff --git a/apps/ota/src/__tests__/version.test.ts b/apps/ota/src/__tests__/version.test.ts
new file mode 100644
index 000000000..d165c6d10
--- /dev/null
+++ b/apps/ota/src/__tests__/version.test.ts
@@ -0,0 +1,83 @@
+import { describe, expect, it } from "vitest"
+
+import type { OtaRelease } from "../lib/schema"
+import { compareSemver, selectLatestCompatibleRelease } from "../lib/version"
+
+function createRelease(overrides: Partial<OtaRelease> = {}): OtaRelease {
+  return {
+    schemaVersion: 1,
+    product: "mobile",
+    channel: "production",
+    releaseVersion: "0.4.2",
+    releaseKind: "ota",
+    runtimeVersion: "0.4.1",
+    publishedAt: "2026-04-10T12:00:00Z",
+    git: {
+      tag: "mobile/v0.4.2",
+      commit: "abcdef1234567890",
+    },
+    policy: {
+      storeRequired: false,
+      minSupportedBinaryVersion: "0.4.1",
+      message: null,
+    },
+    platforms: {
+      ios: {
+        launchAsset: {
+          path: "bundles/ios-main.js",
+          sha256: "a".repeat(64),
+          contentType: "application/javascript",
+        },
+        assets: [],
+      },
+    },
+    ...overrides,
+  }
+}
+
+describe("compareSemver", () => {
+  it("orders plain x.y.z versions numerically", () => {
+    expect(compareSemver("0.4.10", "0.4.2")).toBeGreaterThan(0)
+    expect(compareSemver("1.0.0", "1.0.0")).toBe(0)
+    expect(compareSemver("0.4.2", "0.5.0")).toBeLessThan(0)
+  })
+})
+
+describe("selectLatestCompatibleRelease", () => {
+  it("selects the highest OTA release for the same runtime", () => {
+    const result = selectLatestCompatibleRelease(
+      [
+        createRelease({
+          releaseVersion: "0.4.2",
+          git: {
+            tag: "mobile/v0.4.2",
+            commit: "abcdef1234567890",
+          },
+        }),
+        createRelease({
+          releaseVersion: "0.4.3",
+          git: {
+            tag: "mobile/v0.4.3",
+            commit: "bcdef1234567890a",
+          },
+        }),
+        createRelease({
+          releaseVersion: "0.4.4",
+          runtimeVersion: "0.4.3",
+          git: {
+            tag: "mobile/v0.4.4",
+            commit: "cdef1234567890ab",
+          },
+        }),
+      ],
+      {
+        product: "mobile",
+        channel: "production",
+        runtimeVersion: "0.4.1",
+        platform: "ios",
+      },
+    )
+
+    expect(result?.releaseVersion).toBe("0.4.3")
+  })
+})
diff --git a/apps/ota/src/lib/schema.ts b/apps/ota/src/lib/schema.ts
index d17f66069..2cb342d19 100644
--- a/apps/ota/src/lib/schema.ts
+++ b/apps/ota/src/lib/schema.ts
@@ -2,6 +2,9 @@ import { z } from "zod"
 
 const semver = z.string().regex(/^\d+\.\d+\.\d+$/)
 const sha256 = z.string().regex(/^[a-f0-9]{64}$/)
+const otaPlatforms = ["ios", "android", "macos", "windows", "linux"] as const
+
+export const otaPlatformSchema = z.enum(otaPlatforms)
 
 const assetSchema = z.object({
   path: z.string().min(1),
@@ -46,3 +49,6 @@ export const otaReleaseSchema = z.object({
   }),
   platforms: platformsSchema,
 })
+
+export type OtaPlatform = z.infer<typeof otaPlatformSchema>
+export type OtaRelease = z.infer<typeof otaReleaseSchema>
diff --git a/apps/ota/src/lib/version.ts b/apps/ota/src/lib/version.ts
new file mode 100644
index 000000000..1aa07b264
--- /dev/null
+++ b/apps/ota/src/lib/version.ts
@@ -0,0 +1,35 @@
+import type { OtaPlatform, OtaRelease } from "./schema"
+
+export function compareSemver(left: string, right: string) {
+  const leftParts = left.split(".").map(Number)
+  const rightParts = right.split(".").map(Number)
+
+  for (let index = 0; index < 3; index += 1) {
+    const diff = leftParts[index]! - rightParts[index]!
+    if (diff !== 0) {
+      return diff
+    }
+  }
+
+  return 0
+}
+
+export function selectLatestCompatibleRelease(
+  releases: OtaRelease[],
+  input: {
+    product: OtaRelease["product"]
+    channel: OtaRelease["channel"]
+    runtimeVersion: OtaRelease["runtimeVersion"]
+    platform: OtaPlatform
+  },
+) {
+  return (
+    releases
+      .filter((release) => release.product === input.product)
+      .filter((release) => release.channel === input.channel)
+      .filter((release) => release.releaseKind === "ota")
+      .filter((release) => release.runtimeVersion === input.runtimeVersion)
+      .filter((release) => Object.prototype.hasOwnProperty.call(release.platforms, input.platform))
+      .sort((left, right) => compareSemver(right.releaseVersion, left.releaseVersion))[0] ?? null
+  )
+}