Galaxy Watch 4 gets August patch as part of upgrade to One UI 8 Watch OS
Update: For Galaxy Watch 4 users—including BT, LTE, and Classic variants—who were previously stuck on One UI 6, Samsung first rolled out the August 2025 security patch with build IYI1. This was immediately followed by the One UI 8 Watch OS update with build JYK4, which includes the October 2025 security patch.
Original: Samsung has officially launched the stable One UI 8 Watch update for the Galaxy Watch 4. This firmware is built on Wear OS 6 (Android 16) and features Samsung’s latest custom One UI 8 Watch interface. Notably, this update is rolling out to the Galaxy Watch 4 and all subsequent models, fulfilling Samsung’s commitment to provide four years of Android OS upgrades for the Watch 4 series.
The One UI 8 Watch update focuses heavily on personal health and wellness. Building upon its previous software foundation, Samsung has introduced a suite of new features designed to enhance sleep tracking, heart health monitoring, fitness, and nutrition. These tools empower users to develop and maintain healthier daily habits through advanced biometric monitoring and personalized wellness guidance.
Regarding the technical details, the stable One UI 8 Watch OTA update for the Galaxy Watch 4 series carries firmware build JYK4. The update is substantial, weighing in at 1.8 GB, and includes the October 2025 security patch.
Starting today, Galaxy Watch 4 BT LTE Classic variants are receiving the new Wear OS 6 firmware update from Samsung. Here are all the details.
Galaxy Watch 5 series also received One UI 8 Watch OS firmware update featuring build DYK4.
The One UI 8 update represents Samsung’s effort to align its smartwatch operating system with its smartphone counterparts. Notably, Samsung skipped One UI 7 for their watch lineup entirely, jumping directly from One UI 6 Watch to One UI 8. This decision allows for better synchronization between Samsung’s mobile devices and its wearable ecosystem.
What’s new in One UI 8 Watch Update?
One UI 8 Watch focuses on 4 core features Bedtime Guidance, Vascular Load, Running Coach, Antioxidant Index.
- Read the complete One UI 8 Watch changelog here.
- Also, see the list of One UI 8 Watch features coming to which devices
According to Samsung, understanding the psychology of habit formation is crucial to appreciating the significance of One UI 8 Watch’s approach. Research consistently shows that lasting behavioral changes don’t happen overnight – they require sustained effort, consistent feedback, and meaningful motivation. The challenge many face is that unhealthy choices often provide immediate gratification while their negative consequences manifest gradually over time. Conversely, healthy habits may not produce instant visible results but contribute substantially to long-term physical and mental well-being.
Samsung’s latest wearable technology addresses this fundamental challenge by providing instant feedback and actionable insights that bridge the gap between healthy choices and their long-term benefits. By offering real-time data and personalized recommendations, the Galaxy Watch becomes more than just a fitness tracker – it transforms into a comprehensive health companion that guides users toward sustainable wellness practices.
1. Bedtime Guidance: Optimizing Sleep for Peak Performance
Sleep remains one of the most critical yet often overlooked aspects of health management. Dr. Hon Pak, Senior Vice President and Head of Digital Health Team at Samsung Electronics, emphasizes that “sleep remains a cornerstone of our approach to health as it influences physical and mental well-being, social relationships and even work performance.”
The new Bedtime Guidance feature represents a sophisticated approach to sleep optimization that goes beyond simple sleep tracking. This intelligent system analyzes three days of sleep data to evaluate both sleep pressure and circadian rhythm patterns, then recommends an optimal bedtime that maximizes alertness for the following day.
Key capabilities include:
- Personalized bedtime recommendations based on individual lifestyle and sleep patterns
- Consistent reminders to maintain regular sleep schedules
- Recovery assistance for users dealing with irregular sleep patterns
- Integration with existing sleep features including pattern analysis and sleep coaching
This feature proves particularly valuable for individuals recovering from periods of inconsistent sleep or those struggling to maintain regular schedules between weekdays and weekends. By considering these real-world challenges, Bedtime Guidance provides practical, actionable advice that adapts to users’ changing circumstances.
2. Vascular Load: Revolutionary Cardiovascular Health Monitoring
The introduction of Vascular Load monitoring represents a significant advancement in consumer wearable technology. This feature measures the stress placed on the vascular system during sleep, providing unprecedented insights into cardiovascular health that were previously available only through clinical assessments.
The vascular system’s role in delivering oxygen and nutrients throughout the body while removing waste makes it a critical indicator of overall health. During sleep, stress on this system should naturally decrease, but excessive fluctuations can negatively impact cardiovascular wellness. By continuously monitoring these patterns, users gain valuable insights into their heart health and can identify potential concerns before they become serious issues.
The interconnected nature of health factors means Vascular Load also provides insights into:
- Sleep quality and consistency
- Exercise recovery patterns
- Stress level impacts on cardiovascular health
- Lifestyle factors affecting vascular wellness
This holistic approach to health monitoring aligns with Samsung’s vision of providing comprehensive health management tools that consider the interconnected nature of various wellness factors.
3. Running Coach: Personalized Training for Every Fitness Level
Running remains one of the most accessible forms of exercise, yet many enthusiasts struggle with injury prevention and optimal training strategies. The Running Coach feature addresses these challenges by providing personalized training programs based on individual fitness levels and goals.
Many runners experience setbacks due to over-pacing or inadequate training preparation. Running Coach mitigates these risks by offering scientifically-based training recommendations that emphasize both performance improvement and injury prevention. The feature is particularly beneficial for beginners who may lack experience in structured training approaches.
The comprehensive training system includes:
- Initial 12-minute assessment to determine fitness level and running capability
- Performance analysis with running level scoring from 1 to 10
- Customized training plans for 5K, 10K, half marathon, and full marathon distances
- Progressive difficulty increases with achievement-based unlocking of new challenges
- Real-time guidance and motivation during training sessions
This gamification approach to fitness training makes the process more engaging while ensuring users progress safely toward their goals. The system’s ability to adapt to individual progress means that both beginners and experienced runners can benefit from personalized coaching that evolves with their improving fitness levels.
4. Antioxidant Index: Cutting-Edge Nutritional Health Assessment
Perhaps the most innovative feature in One UI 8 Watch is the Antioxidant Index, which represents an industry-first capability in consumer wearable technology. This feature addresses the growing concern about aging and cellular health by measuring carotenoid levels – powerful antioxidants found in green and orange fruits and vegetables.
The science behind this feature is compelling: behavioral factors such as alcohol consumption, smoking, UV exposure, stress, and insufficient sleep accelerate aging by increasing free radicals in the body. These unstable molecules damage cells and contribute to various health issues. Antioxidants neutralize free radicals, helping prevent chronic illness and supporting healthy aging processes.
The Antioxidant Index provides:
- Five-second carotenoid level assessment using advanced BioActive Sensor technology
- Real-time feedback on dietary choices and their impact on antioxidant levels
- Motivation for adopting healthier eating habits through measurable results
- Integration with overall health and wellness tracking
The immediate feedback capability of this feature addresses one of the primary challenges in nutritional health – the difficulty in seeing tangible results from dietary improvements. By providing measurable data that reflects recent dietary choices, users can better understand the impact of their nutritional decisions and feel motivated to maintain healthy eating patterns.
Samsung’s implementation of these advanced health features requires sophisticated sensor technology and data processing capabilities. The BioActive Sensor technology enables multiple health measurements from a single device, while advanced algorithms process complex physiological data to provide meaningful insights.
The integration of these features into the Galaxy Watch ecosystem demonstrates Samsung’s commitment to creating a comprehensive health management platform. Rather than offering isolated features, One UI 8 Watch provides interconnected health insights that work together to support overall wellness goals.
Accessibility and Availability
Samsung has announced that these groundbreaking features will initially be available through a limited beta program for users in Korea and the United States with Galaxy Watch5 series or later models. This phased rollout allows Samsung to gather user feedback and refine the features before broader availability.
The beta program is an opportunity for early adopters to experience cutting-edge health technology while contributing to its development. Users interested in participating should monitor Samsung’s official announcements for enrollment details and eligibility requirements.
