{ "title": "MCP Protocol Versions FAQ", "schemaVersion": "1.0", "researchFreeze": "2026-08-26", "protocolRevision": "2026-07-28", "schemaNote": "This is a public answer dataset, not a claim that FAQPage rich-result markup is appropriate.", "count": 51, "records": [ { "id": "R7-FAQ001", "packageFaqId": "FAQ001", "question": "What is the latest MCP protocol version?", "answerMarkdown": "As of August 26, 2026, the latest released core specification is `2026-07-28`. This is live-check material.", "answer": "As of August 26, 2026, the latest released core specification is 2026-07-28. This is live-check material.", "packageSourceIds": [ "S001", "S017", "S087" ], "sourceIds": [ "S054", "S313", "S336" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ002", "packageFaqId": "FAQ002", "question": "How many released MCP revisions are there?", "answerMarkdown": "Five dated public revisions are central to the released history: `2024-11-05`, `2025-03-26`, `2025-06-18`, `2025-11-25`, and `2026-07-28`.", "answer": "Five dated public revisions are central to the released history: 2024-11-05, 2025-03-26, 2025-06-18, 2025-11-25, and 2026-07-28.", "packageSourceIds": [ "S001", "S027", "S033", "S038", "S044", "S087" ], "sourceIds": [ "S054", "S249", "S035", "S042", "S048", "S336" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ003", "packageFaqId": "FAQ003", "question": "Why are MCP versions dates?", "answerMarkdown": "The date identifies an immutable wire-protocol revision. It is not a semantic software version.", "answer": "The date identifies an immutable wire-protocol revision. It is not a semantic software version.", "packageSourceIds": [ "S004", "S085" ], "sourceIds": [ "S056", "S335" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ004", "packageFaqId": "FAQ004", "question": "Is `2026-07-28` MCP 2.0?", "answerMarkdown": "Not officially. “MCP v2” is an informal or SDK-specific label; the protocol identifier is `2026-07-28`.", "answer": "Not officially. “MCP v2” is an informal or SDK-specific label; the protocol identifier is 2026-07-28.", "packageSourceIds": [ "S004", "S052", "S085" ], "sourceIds": [ "S056", "S252", "S335" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ005", "packageFaqId": "FAQ005", "question": "Is MCP backward compatible?", "answerMarkdown": "Not as a blanket guarantee. Compatibility depends on shared revisions, SDK fallback, transport, auth, capabilities and extensions.", "answer": "Not as a blanket guarantee. Compatibility depends on shared revisions, SDK fallback, transport, auth, capabilities and extensions.", "packageSourceIds": [ "S004", "S053", "S056", "S059", "S066" ], "sourceIds": [ "S056", "S253", "S166", "S325", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ006", "packageFaqId": "FAQ006", "question": "What is the handshake era?", "answerMarkdown": "All released revisions through `2025-11-25`, which begin with `initialize` and use negotiated connection/session state.", "answer": "All released revisions through 2025-11-25, which begin with initialize and use negotiated connection/session state.", "packageSourceIds": [ "S028", "S035", "S040", "S046" ], "sourceIds": [ "S026", "S156", "S159", "S160" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ007", "packageFaqId": "FAQ007", "question": "What is the modern MCP era?", "answerMarkdown": "The `2026-07-28` revision, which removes initialization and protocol sessions and makes requests self-describing.", "answer": "The 2026-07-28 revision, which removes initialization and protocol sessions and makes requests self-describing.", "packageSourceIds": [ "S001", "S002", "S004" ], "sourceIds": [ "S054", "S055", "S056" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ008", "packageFaqId": "FAQ008", "question": "What replaced `initialize`?", "answerMarkdown": "`server/discover` can provide up-front advertisement, while each modern request carries its version and client metadata.", "answer": "server/discover can provide up-front advertisement, while each modern request carries its version and client metadata.", "packageSourceIds": [ "S002", "S004", "S005" ], "sourceIds": [ "S055", "S056", "S127" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ009", "packageFaqId": "FAQ009", "question": "Is `server/discover` mandatory for clients?", "answerMarkdown": "Clients may operate with a known/pinned modern version, but current servers implement discovery and interoperable clients often probe it.", "answer": "Clients may operate with a known/pinned modern version, but current servers implement discovery and interoperable clients often probe it.", "packageSourceIds": [ "S004", "S005" ], "sourceIds": [ "S056", "S127" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ010", "packageFaqId": "FAQ010", "question": "What replaced `Mcp-Session-Id`?", "answerMarkdown": "Nothing at the protocol-session layer. Stateful applications use explicit handles and ordinary storage.", "answer": "Nothing at the protocol-session layer. Stateful applications use explicit handles and ordinary storage.", "packageSourceIds": [ "S002", "S009", "S021", "S022" ], "sourceIds": [ "S055", "S131", "S061", "S316" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ011", "packageFaqId": "FAQ011", "question": "Can one server support old and new MCP clients?", "answerMarkdown": "Yes. Several official SDKs route legacy initialization and modern requests through one server entry point.", "answer": "Yes. Several official SDKs route legacy initialization and modern requests through one server entry point.", "packageSourceIds": [ "S053", "S056", "S057", "S059", "S066" ], "sourceIds": [ "S253", "S166", "S323", "S325", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ012", "packageFaqId": "FAQ012", "question": "Can a new client use a 2025 server?", "answerMarkdown": "Yes if it supports legacy fallback and shares a handshake-era revision.", "answer": "Yes if it supports legacy fallback and shares a handshake-era revision.", "packageSourceIds": [ "S053", "S056", "S057", "S059", "S066" ], "sourceIds": [ "S253", "S166", "S323", "S325", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ013", "packageFaqId": "FAQ013", "question": "Can a 2025 client use a 2026 server?", "answerMarkdown": "Only if that server preserves a compatible legacy path or a gateway translates the interaction.", "answer": "Only if that server preserves a compatible legacy path or a gateway translates the interaction.", "packageSourceIds": [ "S053", "S056", "S057", "S059", "S066" ], "sourceIds": [ "S253", "S166", "S323", "S325", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ014", "packageFaqId": "FAQ014", "question": "Does a modern client always probe `server/discover`?", "answerMarkdown": "No. SDK defaults differ. Some use automatic probing; TypeScript v2 also documents legacy defaults and explicit opt-in modes.", "answer": "No. SDK defaults differ. Some use automatic probing; TypeScript v2 also documents legacy defaults and explicit opt-in modes.", "packageSourceIds": [ "S004", "S053", "S056", "S066" ], "sourceIds": [ "S056", "S253", "S166", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ015", "packageFaqId": "FAQ015", "question": "What is protocol pinning?", "answerMarkdown": "Selecting a known modern revision without negotiation. A pin should fail rather than silently downgrade.", "answer": "Selecting a known modern revision without negotiation. A pin should fail rather than silently downgrade.", "packageSourceIds": [ "S004", "S053", "S056" ], "sourceIds": [ "S056", "S253", "S166" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ016", "packageFaqId": "FAQ016", "question": "What does version negotiation mean before 2026?", "answerMarkdown": "The client proposes a revision in `initialize`; the server returns the selected revision in its initialization result.", "answer": "The client proposes a revision in initialize; the server returns the selected revision in its initialization result.", "packageSourceIds": [ "S028", "S035", "S040", "S046" ], "sourceIds": [ "S026", "S156", "S159", "S160" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ017", "packageFaqId": "FAQ017", "question": "What does version negotiation mean in 2026?", "answerMarkdown": "A client can discover supported versions, select one, and place the selected version in each request.", "answer": "A client can discover supported versions, select one, and place the selected version in each request.", "packageSourceIds": [ "S004", "S005" ], "sourceIds": [ "S056", "S127" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ018", "packageFaqId": "FAQ018", "question": "Which revision introduced Streamable HTTP?", "answerMarkdown": "`2025-03-26`.", "answer": "2025-03-26.", "packageSourceIds": [ "S034", "S036" ], "sourceIds": [ "S036", "S038" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ019", "packageFaqId": "FAQ019", "question": "What happened to HTTP+SSE?", "answerMarkdown": "Streamable HTTP replaced it as the preferred remote transport in March 2025; it was formally deprecated in July 2026.", "answer": "Streamable HTTP replaced it as the preferred remote transport in March 2025; it was formally deprecated in July 2026.", "packageSourceIds": [ "S002", "S029", "S034", "S036" ], "sourceIds": [ "S055", "S027", "S036", "S038" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ020", "packageFaqId": "FAQ020", "question": "Which revision introduced OAuth authorization?", "answerMarkdown": "`2025-03-26` introduced the first core framework.", "answer": "2025-03-26 introduced the first core framework.", "packageSourceIds": [ "S034", "S037" ], "sourceIds": [ "S036", "S037" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ021", "packageFaqId": "FAQ021", "question": "Which revision hardened OAuth resource binding?", "answerMarkdown": "`2025-06-18` formalized the resource-server model, protected-resource metadata and Resource Indicators.", "answer": "2025-06-18 formalized the resource-server model, protected-resource metadata and Resource Indicators.", "packageSourceIds": [ "S039", "S042" ], "sourceIds": [ "S043", "S044" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ022", "packageFaqId": "FAQ022", "question": "Which revision introduced structured tool output?", "answerMarkdown": "`2025-06-18`.", "answer": "2025-06-18.", "packageSourceIds": [ "S011", "S039" ], "sourceIds": [ "S123", "S043" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ023", "packageFaqId": "FAQ023", "question": "When was JSON-RPC batching added?", "answerMarkdown": "`2025-03-26`.", "answer": "2025-03-26.", "packageSourceIds": [ "S034" ], "sourceIds": [ "S036" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ024", "packageFaqId": "FAQ024", "question": "When was JSON-RPC batching removed?", "answerMarkdown": "`2025-06-18`.", "answer": "2025-06-18.", "packageSourceIds": [ "S039" ], "sourceIds": [ "S043" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ025", "packageFaqId": "FAQ025", "question": "Why was batching removed so quickly?", "answerMarkdown": "Implementation experience showed that the newly added behavior was not worth preserving; the changelog records the reversal, while the full rationale lives in project history.", "answer": "Implementation experience showed that the newly added behavior was not worth preserving; the changelog records the reversal, while the full rationale lives in project history.", "packageSourceIds": [ "S034", "S039" ], "sourceIds": [ "S036", "S043" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ026", "packageFaqId": "FAQ026", "question": "Which revision introduced elicitation?", "answerMarkdown": "`2025-06-18`.", "answer": "2025-06-18.", "packageSourceIds": [ "S039", "S043" ], "sourceIds": [ "S043", "S046" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ027", "packageFaqId": "FAQ027", "question": "How did elicitation change in 2026?", "answerMarkdown": "The modern era returns input requirements and retries the outer request through MRTR instead of sending a server-originated request.", "answer": "The modern era returns input requirements and retries the outer request through MRTR instead of sending a server-originated request.", "packageSourceIds": [ "S002", "S014", "S023" ], "sourceIds": [ "S055", "S126", "S317" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ028", "packageFaqId": "FAQ028", "question": "Which revision introduced Tasks?", "answerMarkdown": "`2025-11-25` introduced experimental core Tasks.", "answer": "2025-11-25 introduced experimental core Tasks.", "packageSourceIds": [ "S045", "S049" ], "sourceIds": [ "S049", "S050" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ029", "packageFaqId": "FAQ029", "question": "Are Tasks part of the 2026 core?", "answerMarkdown": "No. They became an official extension.", "answer": "No. They became an official extension.", "packageSourceIds": [ "S002", "S024", "S049" ], "sourceIds": [ "S055", "S137", "S050" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ030", "packageFaqId": "FAQ030", "question": "Are MCP Apps part of the core?", "answerMarkdown": "No. MCP Apps are an extension and require separate host/client support.", "answer": "No. MCP Apps are an extension and require separate host/client support.", "packageSourceIds": [ "S025" ], "sourceIds": [ "S318" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ031", "packageFaqId": "FAQ031", "question": "Are Roots removed?", "answerMarkdown": "No. They are deprecated under the current policy, not yet removed.", "answer": "No. They are deprecated under the current policy, not yet removed.", "packageSourceIds": [ "S002", "S019", "S020" ], "sourceIds": [ "S055", "S315", "S065" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ032", "packageFaqId": "FAQ032", "question": "Is Sampling removed?", "answerMarkdown": "No. It is deprecated and retained during the migration window.", "answer": "No. It is deprecated and retained during the migration window.", "packageSourceIds": [ "S002", "S019", "S020" ], "sourceIds": [ "S055", "S315", "S065" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ033", "packageFaqId": "FAQ033", "question": "Is protocol Logging removed?", "answerMarkdown": "No. It is deprecated; current designs should follow the documented migration path.", "answer": "No. It is deprecated; current designs should follow the documented migration path.", "packageSourceIds": [ "S002", "S019", "S020" ], "sourceIds": [ "S055", "S315", "S065" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ034", "packageFaqId": "FAQ034", "question": "What replaced `resources/subscribe`?", "answerMarkdown": "Modern clients request relevant event streams through `subscriptions/listen`.", "answer": "Modern clients request relevant event streams through subscriptions/listen.", "packageSourceIds": [ "S002", "S012" ], "sourceIds": [ "S055", "S124" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ035", "packageFaqId": "FAQ035", "question": "Does 2026 MCP still use SSE?", "answerMarkdown": "It may use request-scoped SSE and subscription streams. What disappeared was the original HTTP+SSE transport and standalone session stream model.", "answer": "It may use request-scoped SSE and subscription streams. What disappeared was the original HTTP+SSE transport and standalone session stream model.", "packageSourceIds": [ "S007", "S009" ], "sourceIds": [ "S057", "S131" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ036", "packageFaqId": "FAQ036", "question": "Does stateless MCP mean a server cannot maintain state?", "answerMarkdown": "No. It removes hidden protocol-session state, not databases, Tasks, caches, authorization records or explicit handles.", "answer": "No. It removes hidden protocol-session state, not databases, Tasks, caches, authorization records or explicit handles.", "packageSourceIds": [ "S021", "S022" ], "sourceIds": [ "S061", "S316" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ037", "packageFaqId": "FAQ037", "question": "What is an SDK tier?", "answerMarkdown": "A project governance classification covering conformance, completeness, maintenance and documentation—not merely popularity.", "answer": "A project governance classification covering conformance, completeness, maintenance and documentation—not merely popularity.", "packageSourceIds": [ "S050" ], "sourceIds": [ "S073" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ038", "packageFaqId": "FAQ038", "question": "Which SDKs are Tier 1?", "answerMarkdown": "As verified August 26, 2026: TypeScript, Python, C# and Go. This is live-check information.", "answer": "As verified August 26, 2026: TypeScript, Python, C and Go. This is live-check information.", "packageSourceIds": [ "S051" ], "sourceIds": [ "S138" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ039", "packageFaqId": "FAQ039", "question": "Does Tier 1 mean every extension is implemented?", "answerMarkdown": "No. Experimental features and extensions are not required for a tier.", "answer": "No. Experimental features and extensions are not required for a tier.", "packageSourceIds": [ "S050" ], "sourceIds": [ "S073" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ040", "packageFaqId": "FAQ040", "question": "Does an SDK major version equal a protocol revision?", "answerMarkdown": "No. One SDK release can implement several protocol revisions, and a major SDK update may retain legacy wire defaults.", "answer": "No. One SDK release can implement several protocol revisions, and a major SDK update may retain legacy wire defaults.", "packageSourceIds": [ "S004", "S050", "S085" ], "sourceIds": [ "S056", "S073", "S335" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ041", "packageFaqId": "FAQ041", "question": "What protocol versions does Go SDK v1.7+ support?", "answerMarkdown": "Its official matrix lists all five released revisions, with `2026-07-28` as the latest.", "answer": "Its official matrix lists all five released revisions, with 2026-07-28 as the latest.", "packageSourceIds": [ "S059", "S060" ], "sourceIds": [ "S325", "S326" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ042", "packageFaqId": "FAQ042", "question": "Does TypeScript SDK v2 automatically speak 2026 on every connection?", "answerMarkdown": "No. The current migration guide documents explicit modern negotiation for hand-constructed clients/servers.", "answer": "No. The current migration guide documents explicit modern negotiation for hand-constructed clients/servers.", "packageSourceIds": [ "S052", "S053", "S054", "S055" ], "sourceIds": [ "S252", "S253", "S168", "S322" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ043", "packageFaqId": "FAQ043", "question": "Does Python SDK v2 support legacy clients?", "answerMarkdown": "Yes. Its official documentation describes one server application serving both protocol eras.", "answer": "Yes. Its official documentation describes one server application serving both protocol eras.", "packageSourceIds": [ "S056", "S057" ], "sourceIds": [ "S166", "S323" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ044", "packageFaqId": "FAQ044", "question": "What protocol version does ChatGPT use?", "answerMarkdown": "The reviewed public product page does not state one canonical date. Product-level testing or vendor confirmation is required.", "answer": "The reviewed public product page does not state one canonical date. Product-level testing or vendor confirmation is required.", "packageSourceIds": [ "S075" ], "sourceIds": [ "S140" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ045", "packageFaqId": "FAQ045", "question": "What protocol version does VS Code use?", "answerMarkdown": "The reviewed documentation describes features and transports rather than one canonical wire-revision claim; live verification is required.", "answer": "The reviewed documentation describes features and transports rather than one canonical wire-revision claim; live verification is required.", "packageSourceIds": [ "S077" ], "sourceIds": [ "S141" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": true }, { "id": "R7-FAQ046", "packageFaqId": "FAQ046", "question": "Can two MCP-compatible products behave differently?", "answerMarkdown": "Yes. Host policy, capabilities, extensions, model, auth and rendering can differ despite wire compatibility.", "answer": "Yes. Host policy, capabilities, extensions, model, auth and rendering can differ despite wire compatibility.", "packageSourceIds": [ "S073", "S074", "S075", "S076", "S077", "S078", "S079", "S080", "S081", "S082", "S083" ], "sourceIds": [ "S145", "S259", "S140", "S090", "S141", "S265", "S269", "S144", "S274", "S284", "S297" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ047", "packageFaqId": "FAQ047", "question": "How should a server publish its compatibility?", "answerMarkdown": "Name exact protocol revisions, transports, auth profile, capabilities, extensions and package versions.", "answer": "Name exact protocol revisions, transports, auth profile, capabilities, extensions and package versions.", "packageSourceIds": [ "S004", "S050", "S053", "S056" ], "sourceIds": [ "S056", "S073", "S253", "S166" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ048", "packageFaqId": "FAQ048", "question": "How should a client report compatibility failures?", "answerMarkdown": "Separate transport, authorization, version, capability, extension and application errors.", "answer": "Separate transport, authorization, version, capability, extension and application errors.", "packageSourceIds": [ "S004", "S005", "S007", "S010" ], "sourceIds": [ "S056", "S127", "S057", "S133" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ049", "packageFaqId": "FAQ049", "question": "Should a new server support `2025-11-25`?", "answerMarkdown": "That is a product decision. Public or enterprise servers may retain legacy support while usage justifies its operational cost.", "answer": "That is a product decision. Public or enterprise servers may retain legacy support while usage justifies its operational cost.", "packageSourceIds": [ "S004", "S053", "S056", "S059", "S066" ], "sourceIds": [ "S056", "S253", "S166", "S325", "S331" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ050", "packageFaqId": "FAQ050", "question": "Should a new server target only `2026-07-28`?", "answerMarkdown": "Modern-only is reasonable when all intended clients support it and the server documents the requirement.", "answer": "Modern-only is reasonable when all intended clients support it and the server documents the requirement.", "packageSourceIds": [ "S001", "S004" ], "sourceIds": [ "S054", "S056" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false }, { "id": "R7-FAQ051", "packageFaqId": "FAQ051", "question": "How do I test MCP compatibility?", "answerMarkdown": "Run a matrix that covers transport, version selection, lifecycle, capabilities, auth, extensions and cross-host behavior—not only connection success.", "answer": "Run a matrix that covers transport, version selection, lifecycle, capabilities, auth, extensions and cross-host behavior—not only connection success.", "packageSourceIds": [ "S004", "S005", "S007", "S010", "S083" ], "sourceIds": [ "S056", "S127", "S057", "S133", "S297" ], "sourceMappingStatus": "editorially-mapped-to-package-evidence", "verifiedAt": "2026-08-26", "currentAnswerRequiresLiveCheck": false } ] }