How to Upgrade Your KLM Flight: Options & Strategies

Understanding Your KLM Flight Upgrade Possibilities

Securing a more comfortable seat on your next KLM Royal Dutch Airlines journey involves understanding the available upgrade pathways. The prospect of experiencing a higher cabin class, whether it’s Premium Economy, World Business Class, or even just a preferred seat, often seems complex. However, by knowing the system and your options, you can significantly increase your chances of a successful upgrade, turning a standard flight into a more enjoyable travel experience. This article demystifies the process, providing actionable insights to help you navigate KLM's upgrade policies and procedures.

• Upgrades can be initiated during booking or post-purchase.
• Bidding, mileage redemption, and potential standby are key methods.
• Eligibility criteria and fare rules heavily influence upgrade success.
• Proactive planning offers the best chance for a desired seat.

KLM offers several avenues for passengers to elevate their travel experience beyond their original booking. These methods range from proactive choices made during the booking phase to opportunistic last-minute strategies. The airline’s approach aims to fill premium cabins efficiently, creating opportunities for passengers willing to meet certain conditions or invest additional value, whether through monetary bids, frequent flyer miles, or other means. It’s crucial to approach the process with a clear understanding of what each option entails to avoid disappointment and maximize your investment.

The overarching principle behind most airline upgrade systems, including KLM's, is to offer unsold premium seats to a broader audience under specific conditions. This benefits the airline by generating revenue from otherwise empty seats and provides passengers with a potentially more luxurious flight at a reduced cost compared to booking the premium cabin directly. However, success is never guaranteed, and understanding the factors that influence availability is paramount. This begins with recognizing that not all tickets are eligible for all types of upgrades.

Eligibility: The First Hurdle to Clear

Before you even consider bidding or redeeming miles, it's vital to confirm your booking's eligibility. Not all fare classes or ticket types can be upgraded. Generally, tickets purchased in lower fare buckets are more likely to be eligible for upgrades than those already booked in a premium class or on specific promotional fares. KLM's system prioritizes upgrades for passengers holding standard economy tickets, but even within economy, different fare rules apply. Always check the specific terms and conditions associated with your ticket when you book, or consult KLM's customer service if unsure. Some heavily discounted or non-refundable tickets may be excluded from upgrade programs altogether, making a proactive check essential.

Furthermore, the type of flight and route can play a role. While KLM aims to offer upgrades on most of its long-haul routes, short-haul flights may have different policies or fewer upgrade options available. The presence of different cabin classes on the specific aircraft operating your flight is also a determining factor. If the aircraft isn't configured with, for example, Premium Economy or Business Class seats, an upgrade to those classes is impossible. Always verify the aircraft type assigned to your flight via the booking details on KLM's website or app, as these can sometimes change.

The Bidding System: Your Chance to Bid for an Upgrade

One of KLM's most prominent upgrade methods is their auction-style bidding system, often referred to as the 'vantage upgrade'. This process allows passengers to place a bid for a chance to move into a higher cabin class, typically World Business Class on long-haul routes. The system is designed to be flexible, allowing you to propose a price you're willing to pay for the upgrade. However, it’s essential to approach this strategically to avoid overspending or bidding too low and missing out.

The bidding window typically opens shortly after you have confirmed your booking and closes a few days before your flight departure. You'll usually receive an email invitation to bid, or you can check your booking management portal on the KLM website. When placing your bid, consider factors such as the length of the flight, the typical price difference between your current cabin and the desired cabin, and the overall demand for your specific route and travel date. KLM does not provide a minimum bid, but they do offer guidance based on historical data or general price ranges, which can be a helpful starting point.

Setting a Smart Bid Amount

Determining the right bid amount is an art rather than a science. Bidding too low is a common pitfall, as it will likely not be accepted. Conversely, bidding too high means you might pay more than the upgrade is worth to you or more than you would have paid if you had booked directly. To mitigate this error-prevention is key. Research current prices for the higher cabin class for comparable flights. Websites that track airfare can sometimes offer insights. Consider the value of the amenities and comfort offered by the higher class—extra legroom, better meals, lounge access, lie-flat seats in Business Class—and decide what that enhanced experience is worth to you personally.

Many travelers find success by bidding slightly above the lower end of what they perceive as a reasonable range. For example, if research suggests a typical upgrade price might be between $400 and $800, you might consider bidding around $550-$650. Your bid is confidential, and you will only be charged if your bid is successful. KLM will notify you via email a few days before departure, typically between 72 and 24 hours in advance. If your bid is unsuccessful, you retain your original booking and fare, and no charges are made.

Do not hesitate to adjust your bid if KLM provides a suggested range or if you gain more information; however, remember that once submitted, bids are usually final and cannot be changed.

What Happens After You Bid?

After submitting your bid, patience is key. KLM processes bids based on a combination of factors, including the bid amount, availability, your original fare class, and sometimes even your frequent flyer status. If your bid is accepted, you will receive a confirmation email detailing the successful upgrade, and your credit card will be charged for the bid amount. You will then receive an updated booking confirmation reflecting your new cabin class, and you can enjoy the enhanced services from check-in to arrival. This often includes priority check-in, lounge access, and a superior in-flight experience.

If your bid is unsuccessful, you will also be notified by email. The good news is that you will not be charged, and your original ticket remains valid. You can then proceed with your journey in your originally booked cabin. It’s important to manage expectations; upgrades are never guaranteed, and the bidding system is a popular method, meaning competition can be high. For those who value certainty, other methods might be more suitable, but for the strategically minded traveler, the bidding system offers a compelling opportunity for a significantly enhanced journey at a potentially reduced cost.

Using Miles and Vouchers for Upgrades

For members of the SkyTeam alliance or KLM's own Flying Blue frequent flyer program, redeeming miles is another primary method to upgrade your flight. This approach offers a more predictable path to a higher cabin class, provided you have accumulated sufficient miles. Unlike bidding, where you compete against others and prices fluctuate, redeeming miles for an upgrade often involves a fixed redemption value, making it easier to budget and plan.

The process typically begins by searching for upgrade availability for your specific flight. This can often be done directly through the Flying Blue website or by contacting KLM customer service. It's crucial to check for upgrade availability before attempting to redeem your miles, as not all flights or seats will have award availability in the higher cabin classes. If availability exists, you can then proceed to book the upgrade using your accrued miles. The number of miles required will depend on the route, the cabin class you're upgrading to, and sometimes dynamic pricing factors within the Flying Blue program.

How to Redeem Flying Blue Miles for Upgrades

To upgrade using Flying Blue miles, you generally need to have an existing KLM booking. Navigate to 'My Booking' on the KLM website, and if your ticket is eligible and upgrade availability exists, you should see an option to 'Upgrade with Miles' or a similar prompt. Follow the on-screen instructions to view available upgrade options and the corresponding mileage costs. The system will show you how many miles are required for each eligible cabin class upgrade.

Alternatively, you can sometimes book directly with miles for the desired higher cabin class. This is often a better use of miles if the mileage cost is comparable or only slightly higher than upgrading an existing economy ticket, especially if you find a good award availability. It's also worth noting that if you are a Flying Blue Elite member (Silver, Gold, or Platinum), you may have priority access to upgrade availability or receive discounts on the mileage required. Always compare the cost in miles versus the cash price of the higher cabin to ensure it represents good value for your redemption. Remember that taxes and fees will still apply to award upgrades.

Consider upgrading to Premium Economy first if Business Class award availability is scarce; it's often easier to find and offers a significant comfort improvement over standard Economy.

→ How to Go on Standby for a Flight: A Strategy

Vouchers and Other Redemption Options

Beyond standard mileage redemptions, KLM sometimes offers upgrade vouchers or allows the use of other loyalty program benefits. These might be earned through promotions, as compensation for service issues, or as part of premium Flying Blue tiers. If you possess any such vouchers, check their terms and conditions for applicability to flight upgrades. It's always wise to contact KLM customer service directly to confirm how and when these can be applied to your booking, as voucher usage can sometimes be restricted to specific fare types or booking channels.

When using miles or vouchers, pay close attention to the refund and change policies. Upgrades made with miles or vouchers may have different rules than the original ticket, particularly regarding cancellations or changes. Ensure you understand these terms to avoid losing your miles or the value of your voucher should your travel plans change. The key is to use your loyalty currency strategically, prioritizing upgrades that offer the greatest personal value and represent an efficient use of your earned rewards.

Last-Minute Upgrade Tactics: Standby and Other Options

When other methods don't pan out or if you're a spontaneous traveler, last-minute upgrade tactics, including standby options, can be a viable strategy. These approaches are more opportunistic and less predictable, often relying on available seats on the day of departure. While they carry a higher degree of uncertainty, they can sometimes yield significant value if successful.

KLM’s approach to last-minute upgrades often involves checking availability on the day of departure. This might involve approaching the gate agent or the KLM Crown Lounge (if you have access) to inquire about unsold seats in a higher cabin. The success of these efforts depends heavily on how full the premium cabin is and the airline's policies regarding filling remaining seats. It’s essential to manage expectations; these are not guaranteed and depend on a confluence of factors. Be polite, prepared, and understand that a negative response is common.

The Concept of Standby Upgrades

The idea of 'standby' for an upgrade is common in the airline industry, though KLM's specific implementation may differ. It generally refers to being placed on a waiting list for a potential upgrade if seats become available just before departure. This can sometimes be facilitated by checking in early and inquiring with staff, or by having elite status with Flying Blue, which often grants priority on such lists. Some travelers also inquire about the possibility of paying a last-minute 'sweet spot' price at the check-in desk if empty seats are detected.

What is screened for a first-class medieval flight exam is not relevant here. However, the chance of getting on a standby flight for an upgrade can be influenced by your passenger profile, your original fare class, and the number of elite members and higher-tier passengers already booked or on the standby list. For a truly free upgrade on a flight, standby is one of the few theoretical possibilities, but even then, often a fee or miles redemption is involved, especially on carriers like KLM. Trying to get an upgrade on a flight for free requires exceptional circumstances, luck, or specific promotions, which are rare.

Always have your original boarding pass and any confirmation of your upgrade inquiry with you, and be ready to present them if asked by staff.

Inquiring at Check-in or the Gate

A common strategy is to inquire about upgrade possibilities at the check-in counter or the departure gate. After completing check-in, approach the counter and politely ask if any upgrades are available for your flight. You might be offered the chance to purchase an upgrade at a discounted rate, especially if the flight is showing a full premium cabin. If you have elite status, make sure your frequent flyer number is correctly associated with your booking, as this often places you higher on any internal upgrade priority lists.

If you are flying from a hub airport where KLM has a lounge (like Amsterdam Schiphol), and you have lounge access (either through status, a premium ticket, or a day pass), you can sometimes inquire at the lounge reception. Lounge agents may have more visibility into last-minute cabin configurations and availability. However, gate agents often have the final say on boarding passes and last-minute seat assignments. Be aware that gate agents are often under time pressure, so your inquiry should be brief and respectful. This is where the 'how to go on standby for a flight' knowledge becomes relevant, though it's more about inquiry than a formal standby system for upgrades.

KLM Premium Economy: A Stepping Stone Upgrade

For many travelers, the goal isn't always the pinnacle of First or Business Class, but a noticeable step up in comfort from standard Economy. KLM's Premium Economy cabin offers precisely this middle ground, providing a more comfortable and exclusive experience without the full cost associated with its World Business Class. Understanding what Premium Economy entails and how to secure it is a key strategy for many seeking an improved journey.

Premium Economy typically features seats with more legroom, a greater recline, and often a wider seat than standard Economy. Passengers also usually receive enhanced meal service, priority boarding, and increased baggage allowance. These benefits collectively contribute to a more relaxed and productive flight, especially on longer routes. It serves as an excellent 'upgrade' for those who find standard Economy constricting but don't require the full suite of services offered by Business Class.

Booking KLM Premium Economy Directly

The most straightforward way to experience KLM's Premium Economy is to book it directly when you are initially purchasing your ticket. During the booking process on KLM's website or through a travel agent, you will see options for different cabin classes, including Premium Economy on eligible flights. Selecting this option guarantees your upgraded seat and includes all associated benefits from the start. This is often the most cost-effective method if you know you desire the upgrade in advance, as booking closer to departure or attempting to upgrade later can sometimes be more expensive.

When comparing fares, consider the total value proposition. The incremental cost for Premium Economy over standard Economy often represents excellent value for the increased comfort and amenities. For example, if the difference is only a few hundred Euros on a transatlantic flight, the extra space, improved service, and amenities can make it well worth the investment. Always review the specific inclusions for Premium Economy on your chosen route, as offerings can vary slightly by aircraft type and flight duration. This is a clear 'how to get an upgrade on a flight' strategy that is guaranteed from booking.

When booking Premium Economy, look for seats at the front of the cabin for potentially quieter travel and quicker deplaning.

Upgrading to Premium Economy from Economy

If you’ve already booked a standard Economy ticket, you can often upgrade to Premium Economy post-purchase, either by paying the fare difference or, in some cases, by using Flying Blue miles. The procedure is similar to upgrading to Business Class: check your booking management portal online or contact customer service. The cost of upgrading will depend on the fare rules of your original ticket and the availability of Premium Economy seats. If using miles, the redemption rate will be specific to the Premium Economy cabin.

It's important to differentiate between an 'upgrade' to Premium Economy and simply 'changing' your ticket. If you are paying a fare difference, KLM may categorize it as changing your ticket to a higher fare class. If using miles, it’s a redemption for a higher class. The key advantage of Premium Economy is that it's often more accessible in terms of cost and mileage redemption than full Business Class, making it a practical goal for many travelers seeking a better flight experience. It's a substantial improvement over standard Economy and a smart choice for longer journeys.

Comparing Upgrade Options: Bids vs. Miles vs. Direct Booking

Choosing the best method to upgrade your KLM flight involves weighing the pros and cons of each primary strategy: bidding, using miles, or booking directly. Each method has its own set of advantages, disadvantages, and suitability depending on your personal preferences, financial situation, and loyalty program status.

→ How to Upgrade a British Airways Flight

The bidding system offers flexibility and the potential to secure an upgrade at a price you dictate. However, it comes with the highest level of uncertainty. You might bid aggressively and still not get the upgrade, or conversely, overbid and pay more than necessary. If your primary goal is certainty and a predictable cost, bidding is likely not the best approach. Its appeal lies in potentially acquiring a premium seat for less than its market value, but this is speculative.

Suitability of Bidding

The bidding system is best suited for travelers who are not on a strict budget for the upgrade, are willing to take a gamble, and have flexibility in their travel plans. If you're looking for a chance to experience Business Class on a special occasion without the full upfront cost, bidding can be an attractive option. It’s also useful if you've already booked an economy ticket and are looking for a last-minute enhancement. However, it's crucial to set a maximum bid you are comfortable with and stick to it, treating any successful upgrade as a bonus rather than a planned expense.

Suitability of Miles Redemption

Redeeming Flying Blue miles provides a more transparent and predictable path to an upgrade. If you are a frequent flyer with a healthy balance of miles, this can be an excellent way to travel in a higher cabin class without additional cash outlay. The main challenge is the availability of award seats in the desired cabin, which can be limited, especially on popular routes or during peak travel times. If you are proactive and book well in advance, or if you have elite status that grants better access, this method is often highly rewarding.

The direct booking of a premium cabin is the most certain but also the most expensive option. This method guarantees your seat and all associated amenities from the moment of purchase. It is ideal for travelers who prioritize comfort, require specific business facilities, or need absolute certainty for important trips. While it requires the largest initial investment, it eliminates the variables of bidding and availability issues associated with mileage redemptions.

Always compare the total cost of upgrading (bid amount or miles + taxes/fees) against the direct booking price for the higher cabin class to determine the best value.

Avoiding Common Pitfalls and Misconceptions

Navigating the world of flight upgrades can lead to unforeseen complications if common pitfalls are not avoided. Many travelers harbor misconceptions about how upgrades work, leading to missed opportunities or unnecessary frustration. Understanding these potential errors is crucial for a smoother upgrade process.

One of the most frequent mistakes is assuming an upgrade is guaranteed once booked or simply by asking. Airlines operate on strict inventory management, and upgrades are subject to availability, fare rules, and specific program policies. Another misconception is that all tickets are eligible; heavily discounted or promotional fares are often excluded. It's also common for travelers to forget about potential taxes and fees that can apply even when using miles or vouchers for an upgrade.

Misconception 1: Availability Equals Upgrade

Many passengers believe that if they see empty seats in a higher cabin class on the day of travel, they are automatically entitled to one or can easily get one. This is rarely the case. Airlines manage their inventory meticulously, and empty seats might be held for operational reasons, elite passengers, or held in reserve for potential last-minute fare sales. Furthermore, the decision to upgrade is often automated or managed by specific personnel, not simply available to any passenger who notices an empty seat. Always inquire through the official channels.

Misconception 2: Free Upgrades are Commonplace

While there are rare instances of complimentary upgrades due to overbooking or service recovery, these are exceptional and not a reliable strategy. The concept of trying to get an upgrade on a flight for free typically involves winning a contest, having extremely high elite status during a specific promotion, or being fortunate enough to benefit from an operational issue. Relying on 'free' upgrades is generally not a practical approach for most travelers. More realistic is understanding how to get an upgrade on a flight, which usually involves a cost, whether monetary or in miles.

Keep a digital copy of your original booking confirmation and any communication regarding upgrade attempts for your records.

Misconception 3: Bid Amounts are Secretly Revealed

In reality, KLM's bidding system, like most others, does not reveal how much other passengers have bid. While you might guess or infer based on success rates, there's no official transparency. Therefore, setting a bid based on pure speculation can be risky. Grounding your bid on research about typical prices and the value of the upgrade to you personally is a more sound strategy than trying to 'game' an unknowable bidding war. What are the chances of getting on a standby flight for an upgrade? This is highly variable, often low unless you have elite status.

A final pitfall is failing to check the aircraft type. An upgrade might be confirmed, only for the passenger to discover that the aircraft scheduled for their flight has been changed to one without the premium cabin they expected. Always verify the aircraft configuration for your flight, especially if you've booked far in advance or if your flight is prone to equipment changes. Understanding the specific terms and conditions of your ticket and any upgrade offer is your strongest defense against disappointment.

When to Initiate Your KLM Flight Upgrade

The timing of your upgrade attempt can significantly impact your success rate and the cost involved. KLM's various upgrade methods have different optimal windows for initiation, and being aware of these can help you plan effectively.

Broadly speaking, there are three main phases for initiating an upgrade: during the initial booking, after booking but well before departure, and very close to the departure date. Each phase carries its own set of considerations and potential outcomes, and the best approach often depends on your specific situation and priorities.

During Initial Booking

This is often the most straightforward and sometimes the most cost-effective time to secure a higher cabin class. When you are initially searching for flights on KLM's website, you can usually see prices for all available cabin classes, including Premium Economy and World Business Class. If the price difference is acceptable to you, booking directly into the desired cabin class guarantees your seat and associated benefits. This method eliminates the uncertainty of bidding or the scramble for award availability. It’s the preferred choice for travelers who know they want a premium experience and want to lock it in at a predictable price.

Post-Booking, Pre-Departure

After you've confirmed your booking, there's a window of opportunity to upgrade. For the bidding system, KLM typically opens the bidding process a few weeks before departure, and bids are usually accepted or rejected a few days prior to the flight. If you plan to use Flying Blue miles, it's generally best to check for upgrade availability and make the redemption as soon as possible after booking, as award seats in premium cabins are often limited and snapped up quickly. For both methods, KLM often sends email notifications when upgrade opportunities become available, so keep an eye on your inbox.

Set calendar reminders for bid submission deadlines and for when award availability might open if you are pursuing mileage upgrades.

→ What Does Class Q Mean on a Flight?

Last-Minute Opportunities

As discussed, last-minute upgrades are also an option, typically on the day of departure. This involves inquiring at check-in, the gate, or potentially at a lounge. These are opportunistic and less predictable. If you are flexible and don't mind the risk of not getting an upgrade, this can sometimes yield a good deal, especially if the airline needs to fill seats. However, it's crucial not to rely solely on this method for important travel, as it’s far from guaranteed. The success of 'how to go on standby for a flight' for an upgrade depends heavily on the day's load factors.

The ideal timing depends on your risk tolerance and how far in advance you plan. For guaranteed comfort, booking directly or redeeming miles early is best. For a potential bargain, strategic bidding or last-minute inquiries can work, but require a different mindset. Understanding the typical timelines for each method is fundamental to executing your upgrade strategy successfully.

Maximizing Your Chances: Proactive Planning and Status

While luck plays a role in flight upgrades, a proactive approach and leveraging loyalty program benefits can significantly improve your odds. KLM, like most airlines, rewards its loyal customers and those who plan ahead.

The most impactful strategy is consistent engagement with the Flying Blue program. Accumulating miles and achieving elite status (Silver, Gold, Platinum) provides distinct advantages when it comes to upgrades. Elite members often receive priority on upgrade waitlists, may get discounted upgrade rates, or have access to award availability before general members.

The Power of Flying Blue Elite Status

Achieving Silver, Gold, or Platinum status within KLM's Flying Blue program can be a game-changer for upgrade aspirations. Elite members are frequently prioritized when there are limited upgrade seats available, whether through a mileage redemption or a paid upgrade. For instance, if multiple passengers are vying for the same few business class seats, a Platinum member might be selected over a Silver member, or a Silver member over a non-member. This status-based priority applies to both complimentary operational upgrades (though rare) and paid or mileage-based upgrades.

Beyond priority, some elite tiers might offer specific upgrade certificates or benefits that can be applied. For example, certain tiers might grant you the ability to purchase upgrades with miles at a reduced rate or provide complimentary access to higher fare classes during specific promotions. The tangible benefits of loyalty status are designed to enhance the travel experience of their most frequent flyers, and upgrades are a prime example of this.

Ensure your Flying Blue number is correctly entered in your booking details for every KLM flight to accrue miles and gain status benefits.

Booking in Flexible Fare Classes

When you book your initial flight, opting for a more flexible Economy fare class, even if it costs slightly more than the most basic ticket, can sometimes improve your upgrade chances. More flexible fares are often viewed more favorably in upgrade priority systems. While not as impactful as elite status, it can be a subtle factor that helps when airlines are making upgrade decisions, particularly in situations where multiple passengers have similar bid amounts or mileage redemption requests.

When to Check Availability and Bid

The timing of your inquiry is critical. For mileage upgrades, check award availability as soon as you book your flight. For bidding, pay attention to when KLM opens the bidding window for your flight. Airlines typically open bids a few weeks out and confirm them a few days before departure. Being among the first to submit a bid, especially if it's a strong one, might offer a slight advantage. However, KLM states that bids are assessed on multiple factors, not just order of submission, so a higher bid amount is generally more influential than timing alone.

Ultimately, maximizing your chances involves a combination of planning, loyalty, and strategic decision-making. By understanding KLM's upgrade ecosystem and actively participating in their loyalty program, you can turn the aspiration of a better seat into a reality more often.

KLM Contact Information and Support

When navigating the complexities of flight upgrades, having direct access to customer support can be invaluable. Whether you need to clarify eligibility, inquire about availability, or resolve an issue, KLM offers several channels for assistance.

For immediate assistance regarding your booking, including upgrade options, it's always recommended to consult the 'My Booking' section on the KLM website or app first. This self-service portal provides detailed information about your reservation and often allows you to manage upgrades directly. If you cannot find the answers there, reaching out to KLM's customer service is the next logical step.

Contacting KLM Customer Service

KLM provides customer support through various means. The most common method is by telephone. You can find specific phone numbers for your region on the KLM website's 'Contact Us' page. Be prepared for potential wait times, especially during peak travel periods. When you connect with an agent, have your booking reference number (PNR) and ticket number readily available. Clearly state your query regarding flight upgrades, and be specific about the flight and cabin class you are interested in.

Another avenue is through KLM's social media channels. Many airlines, including KLM, offer support via platforms like Twitter or Facebook, where dedicated teams can answer questions and provide assistance, often more quickly than traditional phone lines for straightforward queries. For more detailed or complex issues, email support or a contact form on their website might be available, though response times can vary.

When calling, ask for an agent specializing in reservations or upgrades to ensure you receive the most accurate information.

KLM Social Media and Chat Support

KLM actively uses social media for customer engagement and support. Reaching out via their official Twitter handle or Facebook page can be an effective way to get quick answers to common questions about upgrades, flight status, or booking modifications. While they may not be able to process complex upgrade requests directly on social media, they can often guide you to the right page or department. Some airlines also offer live chat support through their websites, which provides real-time text-based assistance and can be a convenient alternative to phone calls.

For any inquiry related to how to upgrade KLM flight, whether you're considering a bid, miles redemption, or a last-minute standby, customer service can clarify specific eligibility criteria for your ticket, current availability, and the precise steps you need to take. Don't hesitate to contact them if you encounter any ambiguity or require personalized advice tailored to your booking. Their guidance can help prevent errors and ensure you are pursuing the most viable upgrade path.