Last updated: November 13, 2026
This guide covers every DOCSIS 4.0 cable modem and gateway we could confirm in US homes, in CableLabs testing or on offer to cable operators as of November 2026, including Xfinity's XB10 and XD4, Hitron's CODA60 and CODA60V, and the operator models from Gemtek, Sagemcom, Sercomm and Vantiva. It explains why none of them is sold at retail, how to tell a DOCSIS 3.1 modem marketed as "next-gen" from a DOCSIS 4.0 modem, and which DOCSIS 3.1 modem to buy for Xfinity, Spectrum (including former Cox markets) and other cable plans today. Every fact below was checked against CableLabs, Comcast, Hitron and industry reporting on November 13, 2026.
Key Takeaways
- No DOCSIS 4.0 modem is sold at retail as of November 13, 2026. A cable modem needs CableLabs certification before it can be sold in stores, and no DOCSIS 4.0 modem had received full certification as of the latest industry report we found, dated September 29, 2026.
- Every DOCSIS 4.0 modem in a US home is supplied by the provider. Xfinity issues the XB10 gateway and XD4 modem on X-Class plans, and Mediacom uses Hitron's CODA60V in its DOCSIS 4.0 markets.
- A DOCSIS 3.1 modem with a 2.5 Gbps Ethernet port covers Xfinity, Spectrum and Cox plans up to 2 Gbps that allow a customer-owned modem, and it keeps working after your provider upgrades to DOCSIS 4.0.
What is a DOCSIS 4.0 modem?
A DOCSIS 4.0 modem is a cable modem built to the CableLabs DOCSIS 4.0 specification, which supports up to 10 Gbps download and 6 Gbps upload over the coax line already in your home. DOCSIS (Data Over Cable Service Interface Specification) is the standard that lets a cable modem talk to your provider's network, and the version number sets the speed ceiling.
DOCSIS 4.0 comes in two flavors. Full Duplex DOCSIS (FDX) sends upload and download traffic in the same block of spectrum and is Comcast's choice. Extended Spectrum DOCSIS (ESD, also called FDD) keeps upload and download in separate spectrum and stretches the cable plant to 1.8 GHz; Charter, Cox and Mediacom have backed it. "Unified" chips from Broadcom handle both flavors in one modem, while MaxLinear's Puma 8 chip currently supports ESD.
For the full specification, the FDX and ESD differences and the history of the standard, see our explainer on what DOCSIS 4.0 is.
Can you buy a DOCSIS 4.0 modem?
No. As of November 13, 2026, no retailer sells a DOCSIS 4.0 cable modem to consumers, and none appears on the approved lists of the major US cable providers. Every DOCSIS 4.0 modem in service is rented or supplied by the internet provider.
The approved lists confirm it. No DOCSIS 4.0 model appears on the Xfinity approved modem list, which we audited against Comcast's official device page on November 11, 2026, or on the Cox approved modem list or the Spectrum approved modem list.
If a marketplace seller lists a DOCSIS 4.0 modem such as an XB10 or XD4, it is provider equipment. It cannot be activated as a customer-owned modem, because no DOCSIS 4.0 model appears on a major provider's approved list.
Why are there no retail DOCSIS 4.0 modems yet?
Retail DOCSIS 4.0 modems are waiting on certification. CableLabs, the cable industry's standards lab, must certify a DOCSIS device before it can be sold at retail, and no DOCSIS 4.0 modem had passed full certification as of September 29, 2026.
That date comes from Light Reading's interview with Mark Bridges, who becomes CableLabs CEO on January 1, 2027. Bridges said suppliers are "very close on getting to our first certification." We found no announcement of a completed DOCSIS 4.0 certification between that interview and November 13, 2026.
Three more factors slow the retail launch:
- Testing cost. CableLabs lists a certification fee of $195,000 for an FDX-only or ESD-only DOCSIS 4.0 modem and $245,000 for a modem that supports both, compared with $145,000 for a DOCSIS 3.1 modem.
- A small retail market. Dell'Oro Group analyst Jeff Heynen told Light Reading that retail accounts for under 20% of DOCSIS modem shipments, so manufacturers build for cable operators first.
- Few networks to plug into. Comcast and Mediacom are the only US providers we found that have announced commercial DOCSIS 4.0 service for households, and Comcast's DOCSIS 4.0 plans come with Comcast's own equipment.
Before full certification, CableLabs awards a step called DOCSIS 3.1 Verified for Interoperability (VFI). VFI confirms that a DOCSIS 4.0 modem runs properly on an existing DOCSIS 3.1 network. In its June 11, 2026 update, CableLabs listed VFI devices from Gemtek, Hitron, MaxLinear, Sagemcom, Sercomm and Ubee. VFI lets operators place DOCSIS 4.0 modems in homes ahead of network upgrades; it is not a retail certification.
Which DOCSIS 4.0 modems exist right now?
These are the eight DOCSIS 4.0 modems and gateways we could confirm in US homes, in CableLabs verification or on offer to cable operators as of November 13, 2026. None is sold at retail.
| Model | Maker | Device type | Ethernet ports | Where it is used |
|---|---|---|---|---|
| Xfinity XB10 | Sercomm (SG417DBCT) and Vantiva (CGM601TCOM) | Gateway: modem plus tri-band WiFi 7 router | 2 x 10 Gbps, 2 x 1 Gbps | Xfinity X-Class plans |
| Xfinity XD4 | Vantiva (CVA601ZCOM) | Modem only, 2 phone ports | 2 x 10 Gbps | Xfinity X-Class plans |
| Hitron CODA60 | Hitron | Modem only | 1 x 10 Gbps | Cable operators, including Astound |
| Hitron CODA60V | Hitron | Modem with 2 phone ports | 1 x 10 Gbps | Mediacom DOCSIS 4.0 markets |
| Gemtek CAVD-100 | Gemtek | Modem with 2 phone ports | Not listed | Sold directly to operators; VFI April 2026 |
| Sagemcom Fast 3994 | Sagemcom | Modem with phone ports | Not listed | Operators; VFI 2026 |
| Sercomm DOCSIS 4.0 eMTA | Sercomm | Modem with phone ports | Not listed | Developed for Charter, per Light Reading's industry sources; VFI June 2026 |
| Vantiva Marlin Xe (CXA500Z) | Vantiva | Modem only (ESD) | Not listed | Announced for cable operators in September 2024 |
What is the Xfinity DOCSIS 4.0 modem?
Xfinity uses two DOCSIS 4.0 devices: the XB10 gateway and the XD4 modem. Comcast issues both only to customers on X-Class Internet plans in neighborhoods where it has switched on DOCSIS 4.0, and it does not sell either one.
The XB10 is Comcast's newest gateway and, according to Xfinity, the first device to combine Unified DOCSIS 4.0 with WiFi 7. Xfinity lists two 10 Gbps Ethernet ports, two 1 Gbps Ethernet ports, tri-band WiFi with up to 100 connected devices per band, and a maximum data throughput of 10 Gbps. Sercomm and Vantiva each build a version under different model numbers.
The XD4 is a modem with no WiFi. It has two 10 Gbps Ethernet ports and two phone ports, according to CableLabs' energy test listing for Comcast devices. Comcast used it before the XB10 was ready, typically paired with an XB8 gateway running in Ethernet WAN mode for WiFi. An Xfinity employee on Comcast's support forum has stated that X-Class tiers let the XD4 pull two public IP addresses, so both 10 Gbps ports can run at once on separate networks.
Is the Hitron CODA60 a retail modem?
No. Hitron's CODA60 product page states it is "Only sold through Service Providers." The CODA60 is a Puma 8-based DOCSIS 4.0 modem with one 10 Gbps Ethernet port and downstream support up to 1.8 GHz, and it received CableLabs VFI status in 2026.
The CODA60V adds two phone ports and is the modem Mediacom used for its first DOCSIS 4.0 customer launch in Moline, Illinois. Hitron also announced a DOCSIS 4.0 WiFi 7 gateway aimed at cable operators, the CODA6021, in September 2025. Hitron has not announced a retail version of either.
What about ARRIS SURFboard, Motorola and NETGEAR?
We found no announcement of a DOCSIS 4.0 modem from any of the three main retail cable modem brands as of November 13, 2026. Their current top models, including the ARRIS SURFboard S34 and G54, the Motorola B12 and MB8611, and the NETGEAR CM3000, are all DOCSIS 3.1.
When will DOCSIS 4.0 modems be sold at retail?
No manufacturer has announced a retail DOCSIS 4.0 modem or a release date as of November 13, 2026. A retail launch needs three steps in order: CableLabs certification, a provider adding the model to its approved list, and a retail brand putting it on shelves.
The first step is the bottleneck. When the certification program opened in 2023, CableLabs told the trade publication Fierce that testing a device could take "anywhere from three to nine months." Gemtek's DOCSIS 4.0 modem has been under certification review since at least June 2026. Even after the first certification, Comcast's X-Class plans ship with Comcast's own equipment today, so a retail DOCSIS 4.0 modem would also need a provider willing to activate customer-owned units.
We will update this page when the first DOCSIS 4.0 modem is certified or announced for retail.
Is a "DOCSIS 3.1+" or "next-gen" modem the same as DOCSIS 4.0?
No. A modem sold as DOCSIS 3.1+, Ultra 3.1, high-split or Next Gen is a DOCSIS 3.1 modem with upgrades, and its spec label still says DOCSIS 3.1. Check the DOCSIS line on the box or product page, not the marketing name.
Those upgrades are useful today:
- Mid-split and high-split upstream. These settings widen the slice of spectrum used for uploads, from 42 MHz on older systems to 85 MHz (mid-split) or 204 MHz (high-split). That is what unlocks faster upload tiers on Xfinity's and Spectrum's upgraded DOCSIS 3.1 networks.
- Extra downstream channels. DOCSIS 3.1+ adds more OFDM channels, the wide data channels DOCSIS 3.1 introduced, so a DOCSIS 3.1 network can push downloads toward 8 Gbps without a full DOCSIS 4.0 upgrade.
On Xfinity, the label to look for is "Next Gen Speed Tier" on Comcast's approved list. Models with that designation include the ARRIS S34, G36 and G54, the Hitron CODA56, the NETGEAR CM2500 and CM3000, and the Ubiquiti UCI. They support Xfinity's faster DOCSIS 3.1 upload tiers, but not X-Class. Our guide to symmetrical upload speeds on DOCSIS 3.1 explains how far these modems can go.
Which internet providers offer DOCSIS 4.0 service?
Comcast Xfinity and Mediacom are the two US providers we found with announced commercial DOCSIS 4.0 service for households as of November 13, 2026. Charter, which acquired Cox on August 20, 2026 and sells Spectrum service in former Cox markets, is upgrading toward DOCSIS 4.0 but has not announced a commercial DOCSIS 4.0 launch.
- Comcast Xfinity: Launched FDX DOCSIS 4.0 in October 2023 and reached "millions" of homes by March 2026, according to Light Reading. X-Class tiers launched at 300 Mbps, 500 Mbps, 1 Gbps and 2 Gbps symmetrical.
- Mediacom: Launched DOCSIS 4.0 for its first customers in Moline, Illinois with Hitron CODA60V modems, and plans faster upload and download speeds for about 1 million homes by the end of 2026 through DOCSIS 4.0 and fiber upgrades.
- Spectrum (including former Cox markets): Plans DOCSIS 4.0 for about 35% of its legacy Charter footprint and DOCSIS 3.1 at 1.2 GHz for the rest. CEO Chris Winfrey said in August 2026 that high-split upgrades in the Charter footprint finish in 2027. See our guide to Cox modem compatibility after the Spectrum merger.
For every other cable provider, including Optimum, Sparklight, Midco, WOW and Breezeline, see our DOCSIS 4.0 rollout tracker by provider.
Which modem should you buy instead of a DOCSIS 4.0 modem?
Buy a DOCSIS 3.1 modem with a 2.5 Gbps Ethernet port that appears on your provider's approved list. Every model below is rated by Xfinity for wired speeds above 2.3 Gbps, enough for Xfinity's 2 Gig plans.
| Modem | 2.5 Gbps Ethernet port | Xfinity Next Gen Speed Tier | Xfinity max wired speed (Gbps) | Best for |
|---|---|---|---|---|
| ARRIS S34 | Yes | Yes | 2.32 | Xfinity plans with faster uploads |
| Hitron CODA56 | Yes | Yes | 2.33 | Best value with Next Gen uploads |
| NETGEAR CM3000 | Yes | Yes | 2.33 | Multi-gig plans with the heaviest uploads |
| ARRIS S33 | Yes | No | 2.33 | Gigabit plans on Xfinity, Spectrum and Cox |
| Motorola MB8611 | Yes | No | 2.34 | Low latency on gigabit plans |
| Motorola B12 | Yes | No | 2.33 | Multi-gig in a compact case |
| NETGEAR CM2000 | Yes | No | 2.34 | 2 Gig download plans |
Xfinity designations and wired speed ratings come from Comcast's approved device list as we checked it on November 11, 2026. The S33, CODA56, CM3000, MB8611, B12 and CM2000 also appear on both Cox's and Spectrum's approved lists. Spectrum approves customer-owned modems up to its 1 Gig plan; its 2 Gig plan requires Spectrum-supplied equipment.
One caveat for Xfinity customers: the S33 is not on Comcast's Next Gen Speed Tier list. If your Xfinity plan advertises upload speeds of 200 Mbps or more, choose the S34, CODA56 or CM3000 instead. For picks by speed tier and provider, see our guide to the best DOCSIS 3.1 modems.
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Should you wait for DOCSIS 4.0 or buy a DOCSIS 3.1 modem now?
Buy a DOCSIS 3.1 modem now. Waiting does not get you a DOCSIS 4.0 modem you can own, because none is for sale, and Xfinity's X-Class plans already include Comcast's DOCSIS 4.0 equipment.
DOCSIS is backward compatible. A DOCSIS 3.1 modem keeps working after your provider upgrades your neighborhood to DOCSIS 4.0; it keeps its current download speeds but cannot reach the symmetrical upload tiers. A refurbished DOCSIS 3.1 modem also starts saving you the rental fee from the first month. Our guide to owning your modem walks through the payback math, and our DOCSIS 3.1 vs DOCSIS 4.0 comparison covers the upgrade decision in depth.
FAQ
Can I use my own modem on Xfinity X-Class?
Not today. X-Class plans run on Comcast-supplied DOCSIS 4.0 equipment, either the XB10 gateway or the XD4 modem, and Xfinity's approved list of customer-owned modems contained no DOCSIS 4.0 models when we checked it on November 11, 2026. You can connect your own router to one of the XD4's 10 Gbps Ethernet ports.
Will my DOCSIS 3.1 modem work after my provider upgrades to DOCSIS 4.0?
Yes. DOCSIS 4.0 networks support DOCSIS 3.1 modems, so your modem keeps its current plan speeds. You lose access only to the symmetrical multi-gig tiers that need DOCSIS 4.0 hardware.
Is there a DOCSIS 4.0 router?
Routers do not use DOCSIS; the standard covers only the modem's connection to the coax line. The DOCSIS 4.0 modem and router combos in use are provider gateways, such as Xfinity's XB10 and Hitron's operator-only CODA6021. To get full multi-gig speed from any modem, pair it with a router that has a 2.5 Gbps or 10 Gbps WAN port, such as the picks in our WiFi 7 router guide.
How do I know if DOCSIS 4.0 is available at my address?
On Xfinity, sign in at xfinity.com or the Xfinity app and check whether X-Class plans are offered at your address; if they are, DOCSIS 4.0 is live there. On other providers, ask whether symmetrical multi-gig plans are available and whether they require new equipment. Our rollout tracker lists each provider's status.
How fast are DOCSIS 4.0 plans today?
Comcast launched X-Class with symmetrical tiers of 300 Mbps, 500 Mbps, 1 Gbps and 2 Gbps. The DOCSIS 4.0 specification allows up to 10 Gbps download and 6 Gbps upload, and CableLabs reports DOCSIS 4.0 modems passing more than 9 Gbps downstream and 2 Gbps upstream in interoperability testing.
Do DOCSIS 4.0 modems support home phone service?
Several do. The Xfinity XD4 has two phone ports, the Hitron CODA60V has two, and Gemtek's CAVD-100 has two VoIP ports. Like all DOCSIS 4.0 equipment today, these come from your provider, which also activates the phone line.
Is DOCSIS 4.0 as fast as fiber?
DOCSIS 4.0 brings cable close to consumer fiber on symmetrical multi-gig speed, with a 6 Gbps upload ceiling in the specification. Fiber still reaches higher, with symmetrical plans of 8 Gbps and more sold in some markets. The advantage of DOCSIS 4.0 is that it uses the coax already in your walls.
