diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66385d5a..7e398a71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+### v4.0.2 (2026-01-30)
+* * *
+
+### New Features:
+* Add custom field filtering support for list operations using type-safe filters.
+
 ### v4.0.1 (2026-01-19)
 * * * 
 
diff --git a/Makefile b/Makefile
new file mode 100644
index 00000000..bd646f56
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,89 @@
+.PHONY: update-version increment-major increment-minor increment-patch test build clean install check
+
+# Version file location
+VERSION_FILE := VERSION
+BUILD_GRADLE_FILE := build.gradle.kts
+
+# Gradle commands
+GRADLE := ./gradlew
+
+update-version:
+	@echo "$(VERSION)" > $(VERSION_FILE)
+	@perl -pi -e 's|version = "[.\-\d\w]+"|version = "$(VERSION)"|' $(BUILD_GRADLE_FILE)
+	@echo "Updated version to $(VERSION)"
+
+increment-major:
+	$(eval CURRENT := $(shell cat $(VERSION_FILE)))
+	$(eval MAJOR := $(shell echo $(CURRENT) | cut -d. -f1))
+	$(eval NEW_VERSION := $(shell echo $$(($(MAJOR) + 1)).0.0))
+	@$(MAKE) update-version VERSION=$(NEW_VERSION)
+	@echo "Version bumped from $(CURRENT) to $(NEW_VERSION)"
+
+increment-minor:
+	$(eval CURRENT := $(shell cat $(VERSION_FILE)))
+	$(eval MAJOR := $(shell echo $(CURRENT) | cut -d. -f1))
+	$(eval MINOR := $(shell echo $(CURRENT) | cut -d. -f2))
+	$(eval NEW_VERSION := $(MAJOR).$(shell echo $$(($(MINOR) + 1))).0)
+	@$(MAKE) update-version VERSION=$(NEW_VERSION)
+	@echo "Version bumped from $(CURRENT) to $(NEW_VERSION)"
+
+increment-patch:
+	$(eval CURRENT := $(shell cat $(VERSION_FILE)))
+	$(eval MAJOR := $(shell echo $(CURRENT) | cut -d. -f1))
+	$(eval MINOR := $(shell echo $(CURRENT) | cut -d. -f2))
+	$(eval PATCH := $(shell echo $(CURRENT) | cut -d. -f3))
+	$(eval NEW_VERSION := $(MAJOR).$(MINOR).$(shell echo $$(($(PATCH) + 1))))
+	@$(MAKE) update-version VERSION=$(NEW_VERSION)
+	@echo "Version bumped from $(CURRENT) to $(NEW_VERSION)"
+
+install:
+	@echo "Installing dependencies..."
+	@$(GRADLE) dependencies
+
+test:
+	@echo "Running tests..."
+	@$(GRADLE) test
+
+test-coverage:
+	@echo "Running tests with coverage..."
+	@$(GRADLE) test jacocoTestReport
+	@echo "Coverage report generated in build/reports/jacoco/test/html/index.html"
+
+security-check:
+	@echo "Running OWASP dependency check..."
+	@$(GRADLE) dependencyCheckAnalyze
+
+check: test
+	@echo "All checks passed!"
+
+build: clean
+	@echo "Building project..."
+	@$(GRADLE) build
+
+clean:
+	@echo "Cleaning build artifacts..."
+	@$(GRADLE) clean
+	@rm -rf build/
+	@rm -rf dist/
+	@rm -rf target/
+	@find . -type f -name '.DS_Store' -delete
+
+javadoc:
+	@echo "Generating Javadoc..."
+	@$(GRADLE) javadoc
+
+jar:
+	@echo "Building JAR..."
+	@$(GRADLE) jar
+
+assemble:
+	@echo "Assembling artifacts..."
+	@$(GRADLE) assemble
+
+update:
+	@echo "Updating dependencies..."
+	@$(GRADLE) dependencies --refresh-dependencies
+
+outdated:
+	@echo "Checking for outdated dependencies..."
+	@$(GRADLE) dependencyUpdates
diff --git a/README.md b/README.md
index d79e12f9..8da1f945 100644
--- a/README.md
+++ b/README.md
@@ -185,6 +185,20 @@ future.thenAccept(resp -> {
 });
 ```
 
+### Custom Field Filtering
+
+Filter list operations by custom fields using type-safe filters (`stringFilter()`, `numberFilter()`, `timestampFilter()`, `booleanFilter()`):
+
+```java
+CustomerListParams params = CustomerListParams.builder()
+    .customField("cf_plan_tier").stringFilter().in("gold", "platinum")
+    .customField("cf_is_vip").booleanFilter().is(true)
+    .customField("cf_total_spent").numberFilter().gte(5000L)
+    .build();
+
+CustomerListResponse response = client.customers().list(params);
+```
+
 ### Exception Handling
 
 The library provides a comprehensive exception hierarchy with **strongly-typed error enums** to handle different types of errors that may occur during API operations.
diff --git a/VERSION b/VERSION
new file mode 100644
index 00000000..ee74734a
--- /dev/null
+++ b/VERSION
@@ -0,0 +1 @@
+4.1.0
diff --git a/build.gradle.kts b/build.gradle.kts
index a1c68d92..7ec634a5 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -7,7 +7,7 @@ plugins {
 }
 
 group = "com.chargebee"
-version = "4.0.1"
+version = "4.1.0"
 description = "Java client library for ChargeBee"
 
 // Project metadata
diff --git a/src/main/java/com/chargebee/v4/filters/BooleanFilter.java b/src/main/java/com/chargebee/v4/filters/BooleanFilter.java
new file mode 100644
index 00000000..1488ca8a
--- /dev/null
+++ b/src/main/java/com/chargebee/v4/filters/BooleanFilter.java
@@ -0,0 +1,36 @@
+/*
+ * This file is auto-generated by Chargebee.
+ * Copyright 2025 Chargebee Inc.
+ */
+
+package com.chargebee.v4.filters;
+
+import java.util.Map;
+
+/**
+ * Filter for boolean fields supporting is, isPresent operations.
+ *
+ * @param <B> The builder type to return for method chaining
+ */
+public class BooleanFilter<B> {
+
+  protected final String fieldName;
+  protected final B builder;
+  protected final Map<String, Object> params;
+
+  public BooleanFilter(String fieldName, B builder, Map<String, Object> params) {
+    this.fieldName = fieldName;
+    this.builder = builder;
+    this.params = params;
+  }
+
+  public B is(Boolean value) {
+    params.put(fieldName + "[is]", String.valueOf(value));
+    return builder;
+  }
+
+  public B isPresent(boolean value) {
+    params.put(fieldName + "[is_present]", String.valueOf(value));
+    return builder;
+  }
+}
diff --git a/src/main/java/com/chargebee/v4/filters/CustomFieldSelector.java b/src/main/java/com/chargebee/v4/filters/CustomFieldSelector.java
new file mode 100644
index 00000000..1196ab8d
--- /dev/null
+++ b/src/main/java/com/chargebee/v4/filters/CustomFieldSelector.java
@@ -0,0 +1,71 @@
+/*
+ * This file is auto-generated by Chargebee.
+ * Copyright 2025 Chargebee Inc.
+ */
+
+package com.chargebee.v4.filters;
+
+import java.util.Map;
+
+/**
+ * Selector for custom field filters. Allows choosing the appropriate filter type
+ * (string, number, timestamp, boolean) for a custom field.
+ *
+ * @param <B> The builder type to return for method chaining
+ */
+public class CustomFieldSelector<B> {
+
+  private final String fieldName;
+  private final B builder;
+  private final Map<String, Object> params;
+
+  public CustomFieldSelector(String fieldName, B builder, Map<String, Object> params) {
+    this.fieldName = fieldName;
+    this.builder = builder;
+    this.params = params;
+  }
+
+  /**
+   * Create a string filter for this custom field.
+   * Supports is, isNot, startsWith, in, notIn, isPresent operations.
+   *
+   * @return StringFilter for the custom field
+   */
+  public StringFilter<B> stringFilter() {
+    return new StringFilter<>(fieldName, builder, params)
+        .supportsPresenceOperator(true)
+        .supportsMultiOperators(true);
+  }
+
+  /**
+   * Create a number filter for this custom field.
+   * Supports is, isNot, lt, lte, gt, gte, between, isPresent operations.
+   *
+   * @return NumberFilter for the custom field
+   */
+  public NumberFilter<B> numberFilter() {
+    return new NumberFilter<>(fieldName, builder, params)
+        .supportsPresenceOperator(true);
+  }
+
+  /**
+   * Create a timestamp filter for this custom field.
+   * Supports on, before, after, between, isPresent operations.
+   *
+   * @return TimestampFilter for the custom field
+   */
+  public TimestampFilter<B> timestampFilter() {
+    return new TimestampFilter<>(fieldName, builder, params)
+        .supportsPresenceOperator(true);
+  }
+
+  /**
+   * Create a boolean filter for this custom field.
+   * Supports is, isPresent operations.
+   *
+   * @return BooleanFilter for the custom field
+   */
+  public BooleanFilter<B> booleanFilter() {
+    return new BooleanFilter<>(fieldName, builder, params);
+  }
+}
diff --git a/src/main/java/com/chargebee/v4/models/addon/params/AddonListParams.java b/src/main/java/com/chargebee/v4/models/addon/params/AddonListParams.java
index b5d808bf..1121c762 100644
--- a/src/main/java/com/chargebee/v4/models/addon/params/AddonListParams.java
+++ b/src/main/java/com/chargebee/v4/models/addon/params/AddonListParams.java
@@ -12,6 +12,8 @@
 import com.chargebee.v4.filters.NumberFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -110,6 +112,19 @@ public AddonListBuilder includeDeleted(Boolean value) {
       return this;
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<AddonListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public AddonListParams build() {
       return new AddonListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/coupon/params/CouponListParams.java b/src/main/java/com/chargebee/v4/models/coupon/params/CouponListParams.java
index 502d4ff9..447d6151 100644
--- a/src/main/java/com/chargebee/v4/models/coupon/params/CouponListParams.java
+++ b/src/main/java/com/chargebee/v4/models/coupon/params/CouponListParams.java
@@ -11,6 +11,8 @@
 import com.chargebee.v4.filters.StringFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -99,6 +101,19 @@ public ApplicableItemPriceIdsFilter applicableItemPriceIds() {
       return new ApplicableItemPriceIdsFilter("applicable_item_price_ids", this, queryParams);
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<CouponListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public CouponListParams build() {
       return new CouponListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/customer/params/CustomerListParams.java b/src/main/java/com/chargebee/v4/models/customer/params/CustomerListParams.java
index d9ef947e..a4d75587 100644
--- a/src/main/java/com/chargebee/v4/models/customer/params/CustomerListParams.java
+++ b/src/main/java/com/chargebee/v4/models/customer/params/CustomerListParams.java
@@ -11,6 +11,8 @@
 import com.chargebee.v4.filters.StringFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -125,6 +127,19 @@ public CustomerListBuilder relationship(RelationshipParams value) {
       return this;
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<CustomerListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public CustomerListParams build() {
       return new CustomerListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/feature/params/FeatureListParams.java b/src/main/java/com/chargebee/v4/models/feature/params/FeatureListParams.java
index d8ae9356..7e6db631 100644
--- a/src/main/java/com/chargebee/v4/models/feature/params/FeatureListParams.java
+++ b/src/main/java/com/chargebee/v4/models/feature/params/FeatureListParams.java
@@ -10,6 +10,8 @@
 import com.chargebee.v4.internal.Recommended;
 import com.chargebee.v4.filters.StringFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -70,6 +72,19 @@ public TypeFilter type() {
       return new TypeFilter("type", this, queryParams);
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<FeatureListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public FeatureListParams build() {
       return new FeatureListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/itemFamily/params/ItemFamilyListParams.java b/src/main/java/com/chargebee/v4/models/itemFamily/params/ItemFamilyListParams.java
index 780c9c3b..b6bf7124 100644
--- a/src/main/java/com/chargebee/v4/models/itemFamily/params/ItemFamilyListParams.java
+++ b/src/main/java/com/chargebee/v4/models/itemFamily/params/ItemFamilyListParams.java
@@ -11,6 +11,8 @@
 import com.chargebee.v4.filters.StringFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -75,6 +77,19 @@ public IncludeSiteLevelResourcesFilter includeSiteLevelResources() {
       return new IncludeSiteLevelResourcesFilter("include_site_level_resources", this, queryParams);
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<ItemFamilyListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public ItemFamilyListParams build() {
       return new ItemFamilyListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/plan/params/PlanListParams.java b/src/main/java/com/chargebee/v4/models/plan/params/PlanListParams.java
index 4dfede48..f626fba8 100644
--- a/src/main/java/com/chargebee/v4/models/plan/params/PlanListParams.java
+++ b/src/main/java/com/chargebee/v4/models/plan/params/PlanListParams.java
@@ -12,6 +12,8 @@
 import com.chargebee.v4.filters.NumberFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -122,6 +124,19 @@ public PlanListBuilder includeDeleted(Boolean value) {
       return this;
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<PlanListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public PlanListParams build() {
       return new PlanListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/quote/params/QuoteListParams.java b/src/main/java/com/chargebee/v4/models/quote/params/QuoteListParams.java
index a1205cad..7b1de744 100644
--- a/src/main/java/com/chargebee/v4/models/quote/params/QuoteListParams.java
+++ b/src/main/java/com/chargebee/v4/models/quote/params/QuoteListParams.java
@@ -11,6 +11,8 @@
 import com.chargebee.v4.filters.StringFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -88,6 +90,19 @@ public SortBySortBuilder sortBy() {
       return new SortBySortBuilder("sort_by", this);
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<QuoteListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public QuoteListParams build() {
       return new QuoteListParams(this);
     }
diff --git a/src/main/java/com/chargebee/v4/models/subscription/params/SubscriptionListParams.java b/src/main/java/com/chargebee/v4/models/subscription/params/SubscriptionListParams.java
index 0edf5437..06511e02 100644
--- a/src/main/java/com/chargebee/v4/models/subscription/params/SubscriptionListParams.java
+++ b/src/main/java/com/chargebee/v4/models/subscription/params/SubscriptionListParams.java
@@ -12,6 +12,8 @@
 import com.chargebee.v4.filters.NumberFilter;
 import com.chargebee.v4.filters.TimestampFilter;
 
+import com.chargebee.v4.filters.CustomFieldSelector;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -145,6 +147,19 @@ public PlanIdFilter planId() {
       return new PlanIdFilter("plan_id", this, queryParams);
     }
 
+    /**
+     * Create a filter for a custom field.
+     *
+     * @param fieldName the custom field name (must contain "cf_")
+     * @return CustomFieldSelector for choosing filter type
+     */
+    public CustomFieldSelector<SubscriptionListBuilder> customField(String fieldName) {
+      if (fieldName == null || !fieldName.contains("cf_")) {
+        throw new IllegalArgumentException("Custom field name must contain 'cf_'");
+      }
+      return new CustomFieldSelector<>(fieldName, this, queryParams);
+    }
+
     public SubscriptionListParams build() {
       return new SubscriptionListParams(this);
     }