feat(BRIDGE-309): Update to the bridge updater logic corresponding to the version file restructure

internal/updater/types_test.go

@@ -0,0 +1,255 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+package updater
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_ReleaseCategory_UpdateEligible(t *testing.T) {
+	// If release is beta only beta users can update
+	require.True(t, EarlyAccessReleaseCategory.UpdateEligible(EarlyChannel))
+	require.False(t, EarlyAccessReleaseCategory.UpdateEligible(StableChannel))
+
+	// If the release is stable and is the newest then both beta and stable users can update
+	require.True(t, StableReleaseCategory.UpdateEligible(EarlyChannel))
+	require.True(t, StableReleaseCategory.UpdateEligible(StableChannel))
+}
+
+func Test_ReleaseCategory_JsonUnmarshal(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected ReleaseCategory
+		wantErr  bool
+	}{
+		{
+			input:    `{"ReleaseCategory": "EarlyAccess"}`,
+			expected: EarlyAccessReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "Earlyaccess"}`,
+			expected: EarlyAccessReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "earlyaccess"}`,
+			expected: EarlyAccessReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "   earlyaccess   "}`,
+			expected: EarlyAccessReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "Stable"}`,
+			expected: StableReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "Stable   "}`,
+			expected: StableReleaseCategory,
+		},
+		{
+			input:    `{"ReleaseCategory": "stable"}`,
+			expected: StableReleaseCategory,
+		},
+		{
+			input:   `{"ReleaseCategory": "invalid"}`,
+			wantErr: true,
+		},
+	}
+
+	var data struct {
+		ReleaseCategory ReleaseCategory
+	}
+
+	for _, test := range tests {
+		err := json.Unmarshal([]byte(test.input), &data)
+		if err != nil && !test.wantErr {
+			t.Errorf("json.Unmarshal() error = %v, wantErr %v", err, test.wantErr)
+			return
+		}
+
+		if test.wantErr && err == nil {
+			t.Errorf("expected err got nil")
+		}
+
+		if !test.wantErr && data.ReleaseCategory != test.expected {
+			t.Errorf("got %v, want %v", data.ReleaseCategory, test.expected)
+		}
+	}
+}
+
+func Test_ReleaseCategory_JsonMarshal(t *testing.T) {
+	tests := []struct {
+		input struct {
+			ReleaseCategory ReleaseCategory `json:"ReleaseCategory"`
+		}
+		expectedOutput string
+		wantErr        bool
+	}{
+		{
+			input: struct {
+				ReleaseCategory ReleaseCategory `json:"ReleaseCategory"`
+			}{ReleaseCategory: StableReleaseCategory},
+			expectedOutput: `{"ReleaseCategory":"Stable"}`,
+		},
+		{
+			input: struct {
+				ReleaseCategory ReleaseCategory `json:"ReleaseCategory"`
+			}{ReleaseCategory: EarlyAccessReleaseCategory},
+			expectedOutput: `{"ReleaseCategory":"EarlyAccess"}`,
+		},
+		{
+			input: struct {
+				ReleaseCategory ReleaseCategory `json:"ReleaseCategory"`
+			}{ReleaseCategory: 4},
+			wantErr: true,
+		},
+	}
+
+	for _, test := range tests {
+		output, err := json.Marshal(test.input)
+
+		if test.wantErr {
+			if err == nil && len(output) == 0 {
+				t.Errorf("expected error or non-empty output for invalid category")
+				return
+			}
+		} else {
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+				return
+			}
+
+			if string(output) != test.expectedOutput {
+				t.Errorf("json.Marshal() = %v, want %v", string(output), test.expectedOutput)
+			}
+		}
+	}
+}
+
+func Test_FileIdentifier_JsonUnmarshal(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected FileIdentifier
+		wantErr  bool
+	}{
+		{
+			input:    `{"Identifier": "package"}`,
+			expected: PackageIdentifier,
+		},
+		{
+			input:    `{"Identifier": "Package"}`,
+			expected: PackageIdentifier,
+		},
+		{
+			input:    `{"Identifier": "pACKage"}`,
+			expected: PackageIdentifier,
+		},
+		{
+			input:    `{"Identifier": "pACKage    "}`,
+			expected: PackageIdentifier,
+		},
+		{
+			input:    `{"Identifier": "installer"}`,
+			expected: InstallerIdentifier,
+		},
+		{
+			input:    `{"Identifier": "Installer"}`,
+			expected: InstallerIdentifier,
+		},
+		{
+			input:    `{"Identifier": "iNSTaller  "}`,
+			expected: InstallerIdentifier,
+		},
+		{
+			input:   `{"Identifier": "error"}`,
+			wantErr: true,
+		},
+	}
+
+	var data struct {
+		Identifier FileIdentifier
+	}
+
+	for _, test := range tests {
+		err := json.Unmarshal([]byte(test.input), &data)
+		if err != nil && !test.wantErr {
+			t.Errorf("json.Unmarshal() error = %v, wantErr %v", err, test.wantErr)
+			return
+		}
+
+		if test.wantErr && err == nil {
+			t.Errorf("expected err got nil")
+		}
+
+		if !test.wantErr && data.Identifier != test.expected {
+			t.Errorf("got %v, want %v", data.Identifier, test.expected)
+		}
+	}
+}
+
+func Test_FileIdentifier_JsonMarshal(t *testing.T) {
+	tests := []struct {
+		input struct {
+			Identifier FileIdentifier
+		}
+		expectedOutput string
+		wantErr        bool
+	}{
+		{
+			input: struct {
+				Identifier FileIdentifier
+			}{Identifier: PackageIdentifier},
+			expectedOutput: `{"Identifier":"package"}`,
+		},
+		{
+			input: struct {
+				Identifier FileIdentifier
+			}{Identifier: InstallerIdentifier},
+			expectedOutput: `{"Identifier":"installer"}`,
+		},
+		{
+			input: struct {
+				Identifier FileIdentifier
+			}{Identifier: 4},
+			wantErr: true,
+		},
+	}
+
+	for _, test := range tests {
+		output, err := json.Marshal(test.input)
+
+		if test.wantErr {
+			if err == nil && len(output) == 0 {
+				t.Errorf("expected error or non-empty output for invalid identifier")
+				return
+			}
+		} else {
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+				return
+			}
+
+			if string(output) != test.expectedOutput {
+				t.Errorf("json.Marshal() = %v, want %v", string(output), test.expectedOutput)
+			}
+		}
+	}
+}

internal/updater/types_version.go

@@ -0,0 +1,135 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+package updater
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+type ReleaseCategory uint8
+type FileIdentifier uint8
+
+const (
+	EarlyAccessReleaseCategory ReleaseCategory = iota
+	StableReleaseCategory
+)
+
+const (
+	PackageIdentifier FileIdentifier = iota
+	InstallerIdentifier
+)
+
+var (
+	releaseCategoryName = map[uint8]string{ //nolint:gochecknoglobals
+		0: "EarlyAccess",
+		1: "Stable",
+	}
+	releaseCategoryValue = map[string]uint8{ //nolint:gochecknoglobals
+		"earlyaccess": 0,
+		"stable":      1,
+	}
+	fileIdentifierName = map[uint8]string{ //nolint:gochecknoglobals
+		0: "package",
+		1: "installer",
+	}
+	fileIdentifierValue = map[string]uint8{ //nolint:gochecknoglobals
+		"package":   0,
+		"installer": 1,
+	}
+)
+
+func ParseFileIdentifier(s string) (FileIdentifier, error) {
+	s = strings.TrimSpace(strings.ToLower(s))
+	val, ok := fileIdentifierValue[s]
+	if !ok {
+		return FileIdentifier(0), fmt.Errorf("%s is not a valid file identifier", s)
+	}
+
+	return FileIdentifier(val), nil
+}
+
+func (fi FileIdentifier) String() string {
+	return fileIdentifierName[uint8(fi)]
+}
+
+func (fi FileIdentifier) MarshalJSON() ([]byte, error) {
+	return json.Marshal(fi.String())
+}
+
+func (fi *FileIdentifier) UnmarshalJSON(data []byte) (err error) {
+	var fileIdentifier string
+	if err := json.Unmarshal(data, &fileIdentifier); err != nil {
+		return err
+	}
+
+	parsedFileIdentifier, err := ParseFileIdentifier(fileIdentifier)
+	if err != nil {
+		return err
+	}
+
+	*fi = parsedFileIdentifier
+	return nil
+}
+
+func ParseReleaseCategory(s string) (ReleaseCategory, error) {
+	s = strings.TrimSpace(strings.ToLower(s))
+	val, ok := releaseCategoryValue[s]
+	if !ok {
+		return ReleaseCategory(0), fmt.Errorf("%s is not a valid release category", s)
+	}
+
+	return ReleaseCategory(val), nil
+}
+
+func (rc ReleaseCategory) String() string {
+	return releaseCategoryName[uint8(rc)]
+}
+
+func (rc ReleaseCategory) MarshalJSON() ([]byte, error) {
+	return json.Marshal(rc.String())
+}
+
+func (rc *ReleaseCategory) UnmarshalJSON(data []byte) (err error) {
+	var releaseCat string
+	if err := json.Unmarshal(data, &releaseCat); err != nil {
+		return err
+	}
+
+	parsedCat, err := ParseReleaseCategory(releaseCat)
+	if err != nil {
+		return err
+	}
+
+	*rc = parsedCat
+
+	return nil
+}
+
+func (rc ReleaseCategory) UpdateEligible(channel Channel) bool {
+	if channel == StableChannel && rc == StableReleaseCategory {
+		return true
+	}
+
+	if channel == EarlyChannel && rc == EarlyAccessReleaseCategory || rc == StableReleaseCategory {
+		return true
+	}
+
+	return false
+}

internal/updater/updater.go

@@ -29,13 +29,17 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/internal/versioner"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/exp/slices"
 )
 
+const updateFileVersion = 1
+
 var (
 	ErrDownloadVerify              = errors.New("failed to download or verify the update")
 	ErrInstall                     = errors.New("failed to install the update")
 	ErrUpdateAlreadyInstalled      = errors.New("update is already installed")
 	ErrVersionFileDownloadOrVerify = errors.New("failed to download or verify the version file")
+	ErrReleaseUpdatePackageMissing = errors.New("release update package is missing")
 )
 
 type Downloader interface {
@@ -53,6 +57,7 @@ type Updater struct {
 	verifier  *crypto.KeyRing
 	product   string
 	platform  string
+	version   uint
 }
 
 func NewUpdater(ver *versioner.Versioner, verifier *crypto.KeyRing, product, platform string) *Updater {
@@ -62,10 +67,36 @@ func NewUpdater(ver *versioner.Versioner, verifier *crypto.KeyRing, product, pla
 		verifier:  verifier,
 		product:   product,
 		platform:  platform,
+		version:   updateFileVersion,
 	}
 }
 
-func (u *Updater) GetVersionInfo(ctx context.Context, downloader Downloader, channel Channel) (VersionInfo, error) {
+func (u *Updater) GetVersionInfoLegacy(ctx context.Context, downloader Downloader, channel Channel) (VersionInfoLegacy, error) {
+	b, err := downloader.DownloadAndVerify(
+		ctx,
+		u.verifier,
+		u.getVersionFileURLLegacy(),
+		u.getVersionFileURLLegacy()+".sig",
+	)
+	if err != nil {
+		return VersionInfoLegacy{}, fmt.Errorf("%w: %w", ErrVersionFileDownloadOrVerify, err)
+	}
+
+	var versionMap VersionMap
+
+	if err := json.Unmarshal(b, &versionMap); err != nil {
+		return VersionInfoLegacy{}, err
+	}
+
+	version, ok := versionMap[channel]
+	if !ok {
+		return VersionInfoLegacy{}, errors.New("no updates available for this channel")
+	}
+
+	return version, nil
+}
+
+func (u *Updater) GetVersionInfo(ctx context.Context, downloader Downloader) (VersionInfo, error) {
 	b, err := downloader.DownloadAndVerify(
 		ctx,
 		u.verifier,
@@ -76,21 +107,16 @@ func (u *Updater) GetVersionInfo(ctx context.Context, downloader Downloader, cha
 		return VersionInfo{}, fmt.Errorf("%w: %w", ErrVersionFileDownloadOrVerify, err)
 	}
 
-	var versionMap VersionMap
+	var releases VersionInfo
 
-	if err := json.Unmarshal(b, &versionMap); err != nil {
+	if err := json.Unmarshal(b, &releases); err != nil {
 		return VersionInfo{}, err
 	}
 
-	version, ok := versionMap[channel]
-	if !ok {
-		return VersionInfo{}, errors.New("no updates available for this channel")
-	}
-
-	return version, nil
+	return releases, nil
 }
 
-func (u *Updater) InstallUpdate(ctx context.Context, downloader Downloader, update VersionInfo) error {
+func (u *Updater) InstallUpdateLegacy(ctx context.Context, downloader Downloader, update VersionInfoLegacy) error {
 	if u.installer.IsAlreadyInstalled(update.Version) {
 		return ErrUpdateAlreadyInstalled
 	}
@@ -113,13 +139,64 @@ func (u *Updater) InstallUpdate(ctx context.Context, downloader Downloader, upda
 	return nil
 }
 
+func (u *Updater) InstallUpdate(ctx context.Context, downloader Downloader, release Release) error {
+	if u.installer.IsAlreadyInstalled(release.Version) {
+		return ErrUpdateAlreadyInstalled
+	}
+
+	// Find update package
+	idx := slices.IndexFunc(release.File, func(file File) bool {
+		return file.Identifier == PackageIdentifier
+	})
+
+	if idx == -1 {
+		logrus.WithFields(logrus.Fields{
+			"release_version": release.Version,
+		}).Error("Update release does not contain update package")
+		return ErrReleaseUpdatePackageMissing
+	}
+
+	releaseUpdatePackage := release.File[idx]
+
+	b, err := downloader.DownloadAndVerify(
+		ctx,
+		u.verifier,
+		releaseUpdatePackage.URL,
+		releaseUpdatePackage.URL+".sig",
+	)
+	if err != nil {
+		return fmt.Errorf("%w: %w", ErrDownloadVerify, err)
+	}
+
+	if err := u.installer.InstallUpdate(release.Version, bytes.NewReader(b)); err != nil {
+		logrus.WithError(err).Error("Failed to install update")
+		return ErrInstall
+	}
+
+	return nil
+}
+
 func (u *Updater) RemoveOldUpdates() error {
 	return u.versioner.RemoveOldVersions()
 }
 
-// getVersionFileURL returns the URL of the version file.
+// getVersionFileURLLegacy returns the URL of the version file.
 // For example:
 //   - https://protonmail.com/download/bridge/version_linux.json
-func (u *Updater) getVersionFileURL() string {
+func (u *Updater) getVersionFileURLLegacy() string {
 	return fmt.Sprintf("%v/%v/version_%v.json", Host, u.product, u.platform)
 }
+
+// getVersionFileURL returns the URL of the version file.
+// For example:
+//   - https://protonmail.com/download/windows/x86/v1/version.json
+//   - https://protonmail.com/download/linux/x86/v1/version.json
+//   - https://protonmail.com/download/darwin/universal/v1/version.json
+func (u *Updater) getVersionFileURL() string {
+	switch u.platform {
+	case "darwin":
+		return fmt.Sprintf("%v/%v/%v/universal/v%v/version.json", Host, u.product, u.platform, u.version)
+	default:
+		return fmt.Sprintf("%v/%v/%v/x86/v%v/version.json", Host, u.product, u.platform, u.version)
+	}
+}

internal/updater/version.go

@@ -19,10 +19,36 @@ package updater
 
 import (
 	"github.com/Masterminds/semver/v3"
+	"github.com/ProtonMail/proton-bridge/v3/internal/updater/versioncompare"
 )
 
-// VersionInfo is information about one version of the app.
+type File struct {
+	URL            string         `json:"Url"`
+	Sha512CheckSum string         `json:"Sha512CheckSum,omitempty"`
+	Identifier     FileIdentifier `json:"Identifier"`
+}
+
+type Release struct {
+	ReleaseCategory   ReleaseCategory `json:"CategoryName"`
+	Version           *semver.Version
+	SystemVersion     versioncompare.SystemVersion `json:"SystemVersion,omitempty"`
+	RolloutProportion float64
+	MinAuto           *semver.Version `json:"MinAuto,omitempty"`
+	ReleaseNotesPage  string
+	LandingPage       string
+	File              []File `json:"File"`
+}
+
+func (rel Release) IsEmpty() bool {
+	return rel.Version == nil && len(rel.File) == 0
+}
+
 type VersionInfo struct {
+	Releases []Release `json:"Releases"`
+}
+
+// VersionInfoLegacy is information about one version of the app.
+type VersionInfoLegacy struct {
 	// Version is the semantic version of the release.
 	Version *semver.Version
 
@@ -46,6 +72,10 @@ type VersionInfo struct {
 	RolloutProportion float64
 }
 
+func (verInfo VersionInfoLegacy) IsEmpty() bool {
+	return verInfo.Version == nil && verInfo.ReleaseNotesPage == ""
+}
+
 // VersionMap represents the structure of the version.json file.
 // It looks like this:
 //
@@ -79,4 +109,4 @@ type VersionInfo struct {
 //	  }
 //	}.
 
-type VersionMap map[Channel]VersionInfo
+type VersionMap map[Channel]VersionInfoLegacy

internal/updater/version_test.go

@@ -0,0 +1,205 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+package updater
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/Masterminds/semver/v3"
+	"github.com/ProtonMail/proton-bridge/v3/internal/updater/versioncompare"
+)
+
+var mockJSONData = `
+{
+  "Releases": [
+    {
+      "CategoryName": "Stable",
+      "Version": "2.1.0",
+      "ReleaseDate": "2025-01-15T08:00:00Z",
+      "File": [
+        {
+          "Url": "https://downloads.example.com/v2.1.0/MyApp-2.1.0.pkg",
+          "Sha512CheckSum": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+          "Identifier": "package"
+        },
+        {
+          "Url": "https://downloads.example.com/v2.1.0/MyApp-2.1.0.dmg",
+          "Sha512CheckSum": "cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce",
+          "Identifier": "installer"
+        }
+      ],
+      "RolloutProportion": 0.5,
+      "MinAuto": "2.0.0",
+      "Commit": "8f52d45c9f8c31aa391315ea24e40c4a7e0b2c1d",
+      "ReleaseNotesPage": "https://example.com/releases/2.1.0/notes",
+      "LandingPage": "https://example.com/releases/2.1.0"
+    },
+    {
+      "CategoryName": "EarlyAccess",
+      "Version": "2.2.0-beta.1",
+      "ReleaseDate": "2025-01-20T10:00:00Z",
+      "File": [
+        {
+          "Url": "https://downloads.example.com/beta/v2.2.0-beta.1/MyApp-2.2.0-beta.1.pkg",
+          "Sha512CheckSum": "a9f0e44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+          "Identifier": "package"
+        }
+      ],
+      "SystemVersion": {
+        "Minimum": "13"
+      },
+      "RolloutProportion": 0.25,
+      "MinAuto": "2.1.0",
+      "Commit": "3e72d45c9f8c31aa391315ea24e40c4a7e0b2c1d",
+      "ReleaseNotesPage": "https://example.com/releases/2.2.0-beta.1/notes",
+      "LandingPage": "https://example.com/releases/2.2.0-beta.1"
+    },
+    {
+      "CategoryName": "Stable",
+      "Version": "2.0.0",
+      "ReleaseDate": "2024-12-01T09:00:00Z",
+      "File": [
+        {
+          "Url": "https://downloads.example.com/v2.0.0/MyApp-2.0.0.pkg",
+          "Sha512CheckSum": "b5f0e44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+          "Identifier": "package"
+        },
+        {
+          "Url": "https://downloads.example.com/v2.0.0/MyApp-2.0.0.dmg",
+          "Sha512CheckSum": "d583e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce",
+          "Identifier": "installer"
+        }
+      ],
+      "SystemVersion": {
+			"Maximum": "12.0.0",
+			"Minimum": "1.0.0"
+		},
+      "RolloutProportion": 1.0,
+      "MinAuto": "1.9.0",
+      "Commit": "2a42d45c9f8c31aa391315ea24e40c4a7e0b2c1d",
+      "ReleaseNotesPage": "https://example.com/releases/2.0.0/notes",
+      "LandingPage": "https://example.com/releases/2.0.0"
+    }
+  ]
+}
+`
+
+var expectedVersionInfo = VersionInfo{
+	Releases: []Release{
+		{
+			ReleaseCategory:   StableReleaseCategory,
+			Version:           semver.MustParse("2.1.0"),
+			RolloutProportion: 0.5,
+			MinAuto:           semver.MustParse("2.0.0"),
+			File: []File{
+				{
+					URL:        "https://downloads.example.com/v2.1.0/MyApp-2.1.0.pkg",
+					Identifier: PackageIdentifier,
+				},
+				{
+					URL:        "https://downloads.example.com/v2.1.0/MyApp-2.1.0.dmg",
+					Identifier: InstallerIdentifier,
+				},
+			},
+		},
+		{
+			ReleaseCategory:   EarlyAccessReleaseCategory,
+			Version:           semver.MustParse("2.2.0-beta.1"),
+			RolloutProportion: 0.25,
+			MinAuto:           semver.MustParse("2.1.0"),
+			File: []File{
+				{
+					URL:        "https://downloads.example.com/beta/v2.2.0-beta.1/MyApp-2.2.0-beta.1.pkg",
+					Identifier: PackageIdentifier,
+				},
+			},
+			SystemVersion: versioncompare.SystemVersion{Minimum: "13"},
+		},
+		{
+			ReleaseCategory:   StableReleaseCategory,
+			Version:           semver.MustParse("2.0.0"),
+			RolloutProportion: 1.0,
+			MinAuto:           semver.MustParse("1.9.0"),
+			SystemVersion:     versioncompare.SystemVersion{Maximum: "12.0.0", Minimum: "1.0.0"},
+			File: []File{
+				{
+					URL:        "https://downloads.example.com/v2.0.0/MyApp-2.0.0.pkg",
+					Identifier: PackageIdentifier,
+				},
+				{
+					URL:        "https://downloads.example.com/v2.0.0/MyApp-2.0.0.dmg",
+					Identifier: InstallerIdentifier,
+				},
+			},
+		},
+	},
+}
+
+func Test_Releases_JsonParse(t *testing.T) {
+	var versionInfo VersionInfo
+	if err := json.Unmarshal([]byte(mockJSONData), &versionInfo); err != nil {
+		t.Fatalf("Failed to parse JSON: %v", err)
+	}
+
+	if len(expectedVersionInfo.Releases) != len(versionInfo.Releases) {
+		t.Fatalf("expected %d releases, parsed %d releases", len(expectedVersionInfo.Releases), len(versionInfo.Releases))
+	}
+
+	for i, expectedRelease := range expectedVersionInfo.Releases {
+		release := versionInfo.Releases[i]
+
+		if release.ReleaseCategory != expectedRelease.ReleaseCategory {
+			t.Errorf("Release %d: expected category %v, got %v", i, expectedRelease.ReleaseCategory, release.ReleaseCategory)
+		}
+
+		if release.Version.String() != expectedRelease.Version.String() {
+			t.Errorf("Release %d: expected version %s, got %s", i, expectedRelease.Version, release.Version)
+		}
+
+		if release.RolloutProportion != expectedRelease.RolloutProportion {
+			t.Errorf("Release %d: expected rollout proportion %f, got %f", i, expectedRelease.RolloutProportion, release.RolloutProportion)
+		}
+
+		if expectedRelease.MinAuto != nil && release.MinAuto.String() != expectedRelease.MinAuto.String() {
+			t.Errorf("Release %d: expected min auto %s, got %s", i, expectedRelease.MinAuto, release.MinAuto)
+		}
+
+		if expectedRelease.SystemVersion.Minimum != release.SystemVersion.Minimum {
+			t.Errorf("Release %d: expected system version minimum %s, got %s", i, expectedRelease.SystemVersion.Minimum, release.SystemVersion.Minimum)
+		}
+
+		if expectedRelease.SystemVersion.Maximum != release.SystemVersion.Maximum {
+			t.Errorf("Release %d: expected system version minimum %s, got %s", i, expectedRelease.SystemVersion.Maximum, release.SystemVersion.Maximum)
+		}
+
+		if len(release.File) != len(expectedRelease.File) {
+			t.Errorf("Release %d: expected %d files, got %d", i, len(expectedRelease.File), len(release.File))
+		}
+
+		for j, expectedFile := range expectedRelease.File {
+			file := release.File[j]
+			if file.URL != expectedFile.URL {
+				t.Errorf("Release %d, File %d: expected URL %s, got %s", i, j, expectedFile.URL, file.URL)
+			}
+			if file.Identifier != expectedFile.Identifier {
+				t.Errorf("Release %d, File %d: expected Identifier %v, got %v", i, j, expectedFile.Identifier, file.Identifier)
+			}
+		}
+	}
+}

internal/updater/versioncompare/compare_darwin.go

@@ -0,0 +1,134 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+//go:build darwin
+
+package versioncompare
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/elastic/go-sysinfo/types"
+	"github.com/sirupsen/logrus"
+)
+
+func (sysVer SystemVersion) IsHostVersionEligible(log *logrus.Entry, host types.Host, getHostOSVersion func(host types.Host) string) (bool, error) {
+	if sysVer.Minimum == "" && sysVer.Maximum == "" {
+		return true, nil
+	}
+
+	// We use getHostOSVersion simply for testing; It's passed via Bridge.
+	var hostVersion string
+	if getHostOSVersion == nil {
+		hostVersion = host.Info().OS.Version
+	} else {
+		hostVersion = getHostOSVersion(host)
+	}
+
+	log.Debugf("Checking host OS and update system version requirements. Host: %s; Maximum: %s; Minimum: %s",
+		hostVersion, sysVer.Maximum, sysVer.Minimum)
+
+	hostVersionArr := strings.Split(hostVersion, ".")
+	if len(hostVersionArr) == 0 || hostVersion == "" {
+		return true, fmt.Errorf("could not get host version: %v", hostVersion)
+	}
+
+	hostVersionArrInt := make([]int, len(hostVersionArr))
+	for i := 0; i < len(hostVersionArr); i++ {
+		hostNum, err := strconv.Atoi(hostVersionArr[i])
+		if err != nil {
+			// If we receive an alphanumeric version - we should continue with the update and stop checking for
+			// OS version requirements.
+			return true, fmt.Errorf("invalid host version number: %s - %s", hostVersionArr[i], hostVersion)
+		}
+		hostVersionArrInt[i] = hostNum
+	}
+
+	if sysVer.Minimum != "" {
+		pass, err := compareMinimumVersion(hostVersionArrInt, sysVer.Minimum)
+		if err != nil {
+			return false, err
+		}
+
+		if !pass {
+			return false, fmt.Errorf("host version is below minimum: hostVersion %v - minimumVersion %v", hostVersion, sysVer.Minimum)
+		}
+	}
+
+	if sysVer.Maximum != "" {
+		pass, err := compareMaximumVersion(hostVersionArrInt, sysVer.Maximum)
+		if err != nil {
+			return false, err
+		}
+
+		if !pass {
+			return false, fmt.Errorf("host version is above maximum version: hostVersion %v - minimumVersion %v", hostVersion, sysVer.Maximum)
+		}
+	}
+
+	return true, nil
+}
+
+func compareMinimumVersion(hostVersionArr []int, minVersion string) (bool, error) {
+	minVersionArr := strings.Split(minVersion, ".")
+	iterationDepth := min(len(hostVersionArr), len(minVersionArr))
+
+	for i := 0; i < iterationDepth; i++ {
+		hostNum := hostVersionArr[i]
+
+		minNum, err := strconv.Atoi(minVersionArr[i])
+		if err != nil {
+			return false, fmt.Errorf("invalid minimum version number: %s - %s", minVersionArr[i], minVersion)
+		}
+
+		if hostNum < minNum {
+			return false, nil
+		}
+
+		if hostNum > minNum {
+			return true, nil
+		}
+	}
+
+	return true, nil // minVersion is inclusive
+}
+
+func compareMaximumVersion(hostVersionArr []int, maxVersion string) (bool, error) {
+	maxVersionArr := strings.Split(maxVersion, ".")
+	iterationDepth := min(len(maxVersionArr), len(hostVersionArr))
+
+	for i := 0; i < iterationDepth; i++ {
+		hostNum := hostVersionArr[i]
+
+		maxNum, err := strconv.Atoi(maxVersionArr[i])
+		if err != nil {
+			return false, fmt.Errorf("invalid maximum version number: %s - %s", maxVersionArr[i], maxVersion)
+		}
+
+		if hostNum > maxNum {
+			return false, nil
+		}
+
+		if hostNum < maxNum {
+			return true, nil
+		}
+	}
+
+	return true, nil // maxVersion is inclusive
+}

internal/updater/versioncompare/compare_darwin_test.go

@@ -0,0 +1,105 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+//go:build darwin
+
+package versioncompare
+
+import (
+	"testing"
+
+	"github.com/elastic/go-sysinfo"
+	"github.com/elastic/go-sysinfo/types"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_IsHost_EligibleDarwin(t *testing.T) {
+	host, err := sysinfo.Host()
+	require.NoError(t, err)
+
+	testData := []struct {
+		sysVer             SystemVersion
+		getHostOsVersionFn func(host types.Host) string
+		shouldContinue     bool
+		wantErr            bool
+	}{
+		{
+			sysVer:             SystemVersion{Minimum: "9.5", Maximum: "12.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "10.0" },
+			shouldContinue:     true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "9.5.5.5", Maximum: "10.1.1.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "10.0" },
+			shouldContinue:     true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "10.0.1", Maximum: "12.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "10.0" },
+			shouldContinue:     true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "11.0", Maximum: "12.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "10.0" },
+			shouldContinue:     false,
+			wantErr:            true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "11.1.0", Maximum: "12.0.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "11.0.0" },
+			shouldContinue:     false,
+			wantErr:            true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "10.0", Maximum: "12.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "12.0" },
+			shouldContinue:     true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "11.1.0", Maximum: "12.0.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "" },
+			shouldContinue:     true,
+			wantErr:            true,
+		},
+		{
+			sysVer:             SystemVersion{Minimum: "11.1.0", Maximum: "12.0.0"},
+			getHostOsVersionFn: func(_ types.Host) string { return "a.b.c" },
+			shouldContinue:     true,
+			wantErr:            true,
+		},
+		{
+			sysVer:             SystemVersion{},
+			getHostOsVersionFn: func(_ types.Host) string { return "1.2.3" },
+			shouldContinue:     true,
+			wantErr:            false,
+		},
+	}
+
+	for _, test := range testData {
+		l := logrus.WithField("test", "test")
+		shouldContinue, err := test.sysVer.IsHostVersionEligible(l, host, test.getHostOsVersionFn)
+
+		if test.wantErr {
+			require.Error(t, err)
+		} else {
+			require.NoError(t, err)
+		}
+
+		require.Equal(t, test.shouldContinue, shouldContinue)
+	}
+}

internal/updater/versioncompare/compare_linux.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+//go:build linux
+
+package versioncompare
+
+import (
+	"github.com/elastic/go-sysinfo/types"
+	"github.com/sirupsen/logrus"
+)
+
+// IsHostVersionEligible - Checks whether host OS version is eligible for update. Defaults to true on Linux.
+func (sysVer SystemVersion) IsHostVersionEligible(log *logrus.Entry, _ types.Host, _ func(host types.Host) string) (bool, error) {
+	log.Info("Checking host OS version on Linux. Defaulting to true.")
+	return true, nil
+}

internal/updater/versioncompare/compare_windows.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+//go:build windows
+
+package versioncompare
+
+import (
+	"github.com/elastic/go-sysinfo/types"
+	"github.com/sirupsen/logrus"
+)
+
+// IsHostVersionEligible - Checks whether host OS version is eligible for update. Defaults to true on Linux.
+func (sysVer SystemVersion) IsHostVersionEligible(log *logrus.Entry, _ types.Host, _ func(host types.Host) string) (bool, error) {
+	log.Info("Checking host OS version on Windows. Defaulting to true.")
+	return true, nil
+}

internal/updater/versioncompare/types.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2025 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+package versioncompare
+
+import "fmt"
+
+type SystemVersion struct {
+	Minimum string `json:"Minimum,omitempty"`
+	Maximum string `json:"Maximum,omitempty"`
+}
+
+func (sysVer SystemVersion) String() string {
+	return fmt.Sprintf("SystemVersion: Maximum %s, Minimum %s", sysVer.Maximum, sysVer.Minimum)
+}