diff --git a/README.md b/README.md
index 1e2e1e4..2890a32 100644
--- a/README.md
+++ b/README.md
@@ -215,7 +215,7 @@ For Replicas replace `#` with the index number for the replica. E.g.: `REPLICA#_
 | RUN_ON_START (bool) | bool | Run the sync on startup |
 | PRINT_CONFIG_ONLY (bool) | bool | Print current config only and stop the application |
 | CONTINUE_ON_ERROR (bool) | bool | Continue sync on errors |
-| API_PORT (int) | int | API port |
+| API_PORT (int) | int | API port (API is disabled if port is set to 0) |
 | API_USERNAME (string) | string | API username |
 | API_PASSWORD (string) | string | API password |
 | API_DARK_MODE (bool) | bool | API dark mode |
diff --git a/docs/main.go b/docs/main.go
index 02bb473..25aac65 100644
--- a/docs/main.go
+++ b/docs/main.go
@@ -26,14 +26,7 @@ func main() {
 	var buf strings.Builder
 	_, _ = buf.WriteString("| Name | Type | Description |\n")
 	_, _ = buf.WriteString("| :--- | ---- |:----------- |\n")
-	oldStdout := os.Stdout
-	r, w, _ := os.Pipe()
-	os.Stdout = w
-	printEnvTags(reflect.TypeOf(types.Config{}), "")
-	_ = w.Close()
-	envDoc, _ := io.ReadAll(r)
-	os.Stdout = oldStdout
-	_, _ = buf.Write(envDoc)
+	printEnvTags(&buf, reflect.TypeOf(types.Config{}), "")
 
 	// Find the markers and replace content between them
 	startMarker := "<!-- env-doc-start -->"
@@ -57,7 +50,7 @@ func main() {
 }
 
 // printEnvTags recursively prints all fields with `env` tags.
-func printEnvTags(t reflect.Type, prefix string) {
+func printEnvTags(w io.Writer, t reflect.Type, prefix string) {
 	if t.Kind() == reflect.Ptr {
 		t = t.Elem()
 	}
@@ -92,12 +85,12 @@ func printEnvTags(t reflect.Type, prefix string) {
 		}
 
 		if ft.Kind() == reflect.Struct && ft.Name() != "Time" { // skip time.Time
-			printEnvTags(ft, strings.TrimSuffix(combinedTag, "_"))
+			printEnvTags(w, ft, strings.TrimSuffix(combinedTag, "_"))
 		} else if envTag != "" {
 			envVar := strings.Trim(combinedTag, "_") + " (" + ft.Kind().String() + ")"
 			docs := field.Tag.Get("documentation")
 
-			_, _ = fmt.Printf("| %s | %s | %s |\n", envVar, ft.Kind().String(), docs)
+			_, _ = fmt.Fprintf(w, "| %s | %s | %s |\n", envVar, ft.Kind().String(), docs)
 		}
 	}
 }
diff --git a/pkg/config/config.go b/pkg/config/config.go
index acb328e..f09ea46 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -102,8 +102,6 @@ func Get(configFile string, flags Flags) (*AppConfig, error) {
 			"Do not use single replica and numbered (list) replica config combined")
 	}
 
-	handleDeprecatedEnvVars(cfg)
-
 	if cfg.Replica != nil {
 		cfg.Replicas = []types.AdGuardInstance{*cfg.Replica}
 		cfg.Replica = nil
diff --git a/pkg/config/config_test.go b/pkg/config/config_test.go
index 01e3ea2..c4777de 100644
--- a/pkg/config/config_test.go
+++ b/pkg/config/config_test.go
@@ -229,16 +229,6 @@ var _ = Describe("Config", func() {
 					flags.EXPECT().Changed(gm.Any()).Return(false).AnyTimes()
 					flags.EXPECT().GetBool(config.FlagFeatureDNSServerConfig).Return(true, nil).AnyTimes()
 
-					cfg, err := config.Get("../../testdata/config_test_replicas.yaml", flags)
-					Ω(err).ShouldNot(HaveOccurred())
-					Ω(cfg.Get().Features.DNS.ServerConfig).Should(BeFalse())
-				})
-				It("should have the feature dns server config from the config DEPRECATED env var", func() {
-					setEnv("FEATURES_DNS_SERVERCONFIG", "false")
-					flags.EXPECT().Changed(config.FlagFeatureDNSServerConfig).Return(true).AnyTimes()
-					flags.EXPECT().Changed(gm.Any()).Return(false).AnyTimes()
-					flags.EXPECT().GetBool(config.FlagFeatureDNSServerConfig).Return(true, nil).AnyTimes()
-
 					cfg, err := config.Get("../../testdata/config_test_replicas.yaml", flags)
 					Ω(err).ShouldNot(HaveOccurred())
 					Ω(cfg.Get().Features.DNS.ServerConfig).Should(BeFalse())
diff --git a/pkg/config/deprecated_env_test.go b/pkg/config/deprecated_env_test.go
deleted file mode 100644
index aadafa6..0000000
--- a/pkg/config/deprecated_env_test.go
+++ /dev/null
@@ -1,139 +0,0 @@
-package config_test
-
-import (
-	"fmt"
-	"os"
-
-	. "github.com/onsi/ginkgo/v2"
-	. "github.com/onsi/gomega"
-
-	"github.com/bakito/adguardhome-sync/pkg/config"
-)
-
-var envVars = []string{
-	"FEATURES_GENERAL_SETTINGS",
-	"FEATURES_QUERY_LOG_CONFIG",
-	"FEATURES_STATS_CONFIG",
-	"FEATURES_CLIENT_SETTINGS",
-	"FEATURES_SERVICES",
-	"FEATURES_FILTERS",
-	"FEATURES_THEME",
-	"FEATURES_DHCP_SERVER_CONFIG",
-	"FEATURES_DHCP_STATIC_LEASES",
-	"FEATURES_DNS_SERVER_CONFIG",
-	"FEATURES_DNS_ACCESS_LISTS",
-	"FEATURES_DNS_REWRITES",
-	"REPLICA1_INTERFACE_NAME",
-	"REPLICA1_DHCP_SERVER_ENABLED",
-}
-
-var deprecatedEnvVars = []string{
-	"FEATURES_GENERALSETTINGS",
-	"FEATURES_QUERYLOGCONFIG",
-	"FEATURES_STATSCONFIG",
-	"FEATURES_CLIENTSETTINGS",
-	"FEATURES_SERVICES",
-	"FEATURES_FILTERS",
-	"FEATURES_DHCP_SERVERCONFIG",
-	"FEATURES_DHCP_STATICLEASES",
-	"FEATURES_DNS_SERVERCONFIG",
-	"FEATURES_DNS_ACCESSLISTS",
-	"FEATURES_DNS_REWRITES",
-	"REPLICA1_INTERFACENAME",
-	"REPLICA1_DHCPSERVERENABLED",
-}
-
-var _ = Describe("Config", func() {
-	Context("deprecated", func() {
-		BeforeEach(func() {
-			for _, envVar := range deprecatedEnvVars {
-				Ω(os.Setenv(envVar, "false")).ShouldNot(HaveOccurred())
-			}
-		})
-		AfterEach(func() {
-			for _, envVar := range deprecatedEnvVars {
-				Ω(os.Unsetenv(envVar)).ShouldNot(HaveOccurred())
-			}
-		})
-		Context("Get", func() {
-			It("features should be false", func() {
-				cfg, err := config.Get("", nil)
-				Ω(err).ShouldNot(HaveOccurred())
-				verifyFeatures(cfg, false)
-			})
-		})
-	})
-	Context("current", func() {
-		BeforeEach(func() {
-			for _, envVar := range envVars {
-				Ω(os.Unsetenv(envVar)).ShouldNot(HaveOccurred())
-			}
-		})
-		AfterEach(func() {
-			for _, envVar := range envVars {
-				Ω(os.Unsetenv(envVar)).ShouldNot(HaveOccurred())
-			}
-		})
-		Context("Get", func() {
-			It("features should be true by default", func() {
-				cfg, err := config.Get("", nil)
-				Ω(err).ShouldNot(HaveOccurred())
-				verifyFeatures(cfg, true)
-			})
-			It("features should be true by default", func() {
-				cfg, err := config.Get("", nil)
-				Ω(err).ShouldNot(HaveOccurred())
-				verifyFeatures(cfg, true)
-			})
-			It("features should be false", func() {
-				for _, envVar := range envVars {
-					Ω(os.Setenv(envVar, "false")).ShouldNot(HaveOccurred())
-				}
-				cfg, err := config.Get("", nil)
-				Ω(err).ShouldNot(HaveOccurred())
-				verifyFeatures(cfg, false)
-			})
-			Context("interface name", func() {
-				It("should set interface name of replica 1", func() {
-					Ω(os.Setenv("REPLICA1_URL", "https://foo.bar")).ShouldNot(HaveOccurred())
-					Ω(os.Setenv(fmt.Sprintf("REPLICA%s_INTERFACE_NAME", "1"), "eth0")).ShouldNot(HaveOccurred())
-					cfg, err := config.Get("", nil)
-					Ω(err).ShouldNot(HaveOccurred())
-					Ω(cfg.Get().Replicas[0].InterfaceName).Should(Equal("eth0"))
-				})
-			})
-			Context("dhcp server", func() {
-				It("should enable the dhcp server of replica 1", func() {
-					Ω(os.Setenv("REPLICA1_URL", "https://foo.bar")).ShouldNot(HaveOccurred())
-					Ω(os.Setenv(fmt.Sprintf("REPLICA%s_DHCPSERVERENABLED", "1"), "true")).ShouldNot(HaveOccurred())
-					cfg, err := config.Get("", nil)
-					Ω(err).ShouldNot(HaveOccurred())
-					Ω(cfg.Get().Replicas[0].DHCPServerEnabled).ShouldNot(BeNil())
-					Ω(*cfg.Get().Replicas[0].DHCPServerEnabled).Should(BeTrue())
-				})
-				It("should disable the dhcp server of replica 1", func() {
-					Ω(os.Setenv("REPLICA1_URL", "https://foo.bar")).ShouldNot(HaveOccurred())
-					Ω(os.Setenv(fmt.Sprintf("REPLICA%s_DHCPSERVERENABLED", "1"), "false")).ShouldNot(HaveOccurred())
-					cfg, err := config.Get("", nil)
-					Ω(err).ShouldNot(HaveOccurred())
-					Ω(cfg.Get().Replicas[0].DHCPServerEnabled).ShouldNot(BeNil())
-					Ω(*cfg.Get().Replicas[0].DHCPServerEnabled).Should(BeFalse())
-				})
-			})
-		})
-	})
-})
-
-func verifyFeatures(cfg *config.AppConfig, value bool) {
-	Ω(cfg.Get().Features.GeneralSettings).Should(Equal(value))
-	Ω(cfg.Get().Features.QueryLogConfig).Should(Equal(value))
-	Ω(cfg.Get().Features.StatsConfig).Should(Equal(value))
-	Ω(cfg.Get().Features.ClientSettings).Should(Equal(value))
-	Ω(cfg.Get().Features.Services).Should(Equal(value))
-	Ω(cfg.Get().Features.Filters).Should(Equal(value))
-	Ω(cfg.Get().Features.DHCP.ServerConfig).Should(Equal(value))
-	Ω(cfg.Get().Features.DHCP.StaticLeases).Should(Equal(value))
-	Ω(cfg.Get().Features.DNS.ServerConfig).Should(Equal(value))
-	Ω(cfg.Get().Features.DNS.AccessLists).Should(Equal(value))
-	Ω(cfg.Get().Features.DNS.Rewrites).Should(Equal(value))
-}
diff --git a/pkg/config/env.go b/pkg/config/env.go
index 7fd7ac8..03a764e 100644
--- a/pkg/config/env.go
+++ b/pkg/config/env.go
@@ -4,81 +4,12 @@ import (
 	"fmt"
 	"os"
 	"strconv"
-	"strings"
 
 	"github.com/caarlos0/env/v11"
 
 	"github.com/bakito/adguardhome-sync/pkg/types"
-	"github.com/bakito/adguardhome-sync/pkg/utils"
 )
 
-func handleDeprecatedEnvVars(cfg *types.Config) {
-	if val, ok := checkDeprecatedEnvVar("RUNONSTART", "RUN_ON_START"); ok {
-		cfg.RunOnStart, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("API_DARKMODE", "API_DARK_MODE"); ok {
-		cfg.API.DarkMode, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_GENERALSETTINGS", "FEATURES_GENERAL_SETTINGS"); ok {
-		cfg.Features.GeneralSettings, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_QUERYLOGCONFIG", "FEATURES_QUERY_LOG_CONFIG"); ok {
-		cfg.Features.QueryLogConfig, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_STATSCONFIG", "FEATURES_STATS_CONFIG"); ok {
-		cfg.Features.StatsConfig, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_CLIENTSETTINGS", "FEATURES_CLIENT_SETTINGS"); ok {
-		cfg.Features.ClientSettings, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_DHCP_SERVERCONFIG", "FEATURES_DHCP_SERVER_CONFIG"); ok {
-		cfg.Features.DHCP.ServerConfig, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_DHCP_STATICLEASES", "FEATURES_DHCP_STATIC_LEASES"); ok {
-		cfg.Features.DHCP.StaticLeases, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_DNS_ACCESSLISTS", "FEATURES_DNS_ACCESS_LISTS"); ok {
-		cfg.Features.DNS.AccessLists, _ = strconv.ParseBool(val)
-	}
-	if val, ok := checkDeprecatedEnvVar("FEATURES_DNS_SERVERCONFIG", "FEATURES_DNS_SERVER_CONFIG"); ok {
-		cfg.Features.DNS.ServerConfig, _ = strconv.ParseBool(val)
-	}
-
-	if cfg.Replica != nil {
-		if val, ok := checkDeprecatedEnvVar("REPLICA_WEBURL", "REPLICA_WEB_URL"); ok {
-			cfg.Replica.WebURL = val
-		}
-		if val, ok := checkDeprecatedEnvVar("REPLICA_AUTOSETUP", "REPLICA_AUTO_SETUP"); ok {
-			cfg.Replica.AutoSetup, _ = strconv.ParseBool(val)
-		}
-		if val, ok := checkDeprecatedEnvVar("REPLICA_INTERFACENAME", "REPLICA_INTERFACE_NAME"); ok {
-			cfg.Replica.InterfaceName = val
-		}
-		if val, ok := checkDeprecatedEnvVar("REPLICA_DHCPSERVERENABLED", "REPLICA_DHCP_SERVER_ENABLED"); ok {
-			if b, err := strconv.ParseBool(val); err != nil {
-				cfg.Replica.DHCPServerEnabled = utils.Ptr(b)
-			}
-		}
-	}
-}
-
-func checkDeprecatedEnvVar(oldName, newName string) (string, bool) {
-	old, oldOK := os.LookupEnv(oldName)
-	if oldOK {
-		logger.With("deprecated", oldName, "replacement", newName).
-			Warn("Deprecated env variable is used, please use the correct one")
-	}
-	newVal, newOK := os.LookupEnv(newName)
-	if newOK {
-		return newVal, true
-	}
-	return old, oldOK
-}
-
-func checkDeprecatedReplicaEnvVar(oldPattern, newPattern string, replicaID int) (string, bool) {
-	return checkDeprecatedEnvVar(fmt.Sprintf(oldPattern, replicaID), fmt.Sprintf(newPattern, replicaID))
-}
-
 // Manually collect replicas from env.
 func enrichReplicasFromEnv(initialReplicas []types.AdGuardInstance) ([]types.AdGuardInstance, error) {
 	var replicas []types.AdGuardInstance
@@ -108,7 +39,7 @@ func enrichReplicasFromEnv(initialReplicas []types.AdGuardInstance) ([]types.AdG
 	for i := range replicas {
 		reID := i + 1
 
-		// keep previously set value
+		// keep the previously set value
 		replicaDhcpServer := replicas[i].DHCPServerEnabled
 		replicas[i].DHCPServerEnabled = nil
 		if err := env.ParseWithOptions(&replicas[i], env.Options{Prefix: fmt.Sprintf("REPLICA%d_", reID)}); err != nil {
@@ -117,26 +48,6 @@ func enrichReplicasFromEnv(initialReplicas []types.AdGuardInstance) ([]types.AdG
 		if replicas[i].DHCPServerEnabled == nil {
 			replicas[i].DHCPServerEnabled = replicaDhcpServer
 		}
-		if val, ok := checkDeprecatedReplicaEnvVar("REPLICA%d_APIPATH", "REPLICA%d_API_PATH", reID); ok {
-			replicas[i].APIPath = val
-		}
-		if val, ok := checkDeprecatedReplicaEnvVar("REPLICA%d_INSECURESKIPVERIFY", "REPLICA%d_INSECURE_SKIP_VERIFY", reID); ok {
-			replicas[i].InsecureSkipVerify = strings.EqualFold(val, "true")
-		}
-		if val, ok := checkDeprecatedReplicaEnvVar("REPLICA%d_AUTOSETUP", "REPLICA%d_AUTO_SETUP", reID); ok {
-			replicas[i].AutoSetup = strings.EqualFold(val, "true")
-		}
-		if val, ok := checkDeprecatedReplicaEnvVar("REPLICA%d_INTERFACENAME", "REPLICA%d_INTERFACE_NAME", reID); ok {
-			replicas[i].InterfaceName = val
-		}
-
-		if dhcpEnabled, ok := checkDeprecatedReplicaEnvVar("REPLICA%d_DHCPSERVERENABLED", "REPLICA%d_DHCP_SERVER_ENABLED", reID); ok {
-			if strings.EqualFold(dhcpEnabled, "true") {
-				replicas[i].DHCPServerEnabled = utils.Ptr(true)
-			} else if strings.EqualFold(dhcpEnabled, "false") {
-				replicas[i].DHCPServerEnabled = utils.Ptr(false)
-			}
-		}
 		if replicas[i].APIPath == "" {
 			replicas[i].APIPath = "/control"
 		}
diff --git a/pkg/types/types.go b/pkg/types/types.go
index d8df91d..fef0888 100644
--- a/pkg/types/types.go
+++ b/pkg/types/types.go
@@ -27,7 +27,7 @@ type Config struct {
 	// Multiple replica instances
 	Replicas        []AdGuardInstance `json:"replicas,omitempty"        yaml:"replicas,omitempty"        faker:"slice_len=2"`
 	Cron            string            `json:"cron,omitempty"            yaml:"cron,omitempty"                                documentation:"Cron expression for the sync interval"              env:"CRON"`
-	RunOnStart      bool              `json:"runOnStart,omitempty"      yaml:"runOnStart,omitempty"                          documentation:"Run the sung on startup"                            env:"RUN_ON_START"`
+	RunOnStart      bool              `json:"runOnStart,omitempty"      yaml:"runOnStart,omitempty"                          documentation:"Run the sync on startup"                            env:"RUN_ON_START"`
 	PrintConfigOnly bool              `json:"printConfigOnly,omitempty" yaml:"printConfigOnly,omitempty"                     documentation:"Print current config only and stop the application" env:"PRINT_CONFIG_ONLY"`
 	ContinueOnError bool              `json:"continueOnError,omitempty" yaml:"continueOnError,omitempty"                     documentation:"Continue sync on errors"                            env:"CONTINUE_ON_ERROR"`
 	API             API               `json:"api,omitempty"             yaml:"api,omitempty"`
@@ -36,12 +36,12 @@ type Config struct {
 
 // API configuration.
 type API struct {
-	Port     int     `documentation:"API port"      env:"API_PORT"      json:"port,omitempty"     yaml:"port,omitempty"`
-	Username string  `documentation:"API username"  env:"API_USERNAME"  json:"username,omitempty" yaml:"username,omitempty"`
-	Password string  `documentation:"API password"  env:"API_PASSWORD"  json:"password,omitempty" yaml:"password,omitempty"`
-	DarkMode bool    `documentation:"API dark mode" env:"API_DARK_MODE" json:"darkMode,omitempty" yaml:"darkMode,omitempty"`
-	Metrics  Metrics `                                                  json:"metrics,omitempty"  yaml:"metrics,omitempty"`
-	TLS      TLS     `                                                  json:"tls,omitempty"      yaml:"tls,omitempty"`
+	Port     int     `documentation:"API port (API is disabled if port is set to 0)" env:"API_PORT"      json:"port,omitempty"     yaml:"port,omitempty"`
+	Username string  `documentation:"API username"                                   env:"API_USERNAME"  json:"username,omitempty" yaml:"username,omitempty"`
+	Password string  `documentation:"API password"                                   env:"API_PASSWORD"  json:"password,omitempty" yaml:"password,omitempty"`
+	DarkMode bool    `documentation:"API dark mode"                                  env:"API_DARK_MODE" json:"darkMode,omitempty" yaml:"darkMode,omitempty"`
+	Metrics  Metrics `                                                                                   json:"metrics,omitempty"  yaml:"metrics,omitempty"`
+	TLS      TLS     `                                                                                   json:"tls,omitempty"      yaml:"tls,omitempty"`
 }
 
 // Metrics configuration.