{"id":12538,"date":"2026-08-29T09:50:14","date_gmt":"2026-08-29T09:50:14","guid":{"rendered":"https:\/\/cryptonews.uk.com\/?p=12538"},"modified":"2026-08-29T09:50:14","modified_gmt":"2026-08-29T09:50:14","slug":"polygon-labs-issues-urgent-client-upgrade-notice-following-austin-and-kyoto-hardforks","status":"publish","type":"post","link":"https:\/\/cryptonews.uk.com\/?p=12538","title":{"rendered":"Polygon Labs issues urgent client upgrade notice following Austin and Kyoto hardforks"},"content":{"rendered":"<p><\/p>\n<div data-single-article-content=\"\">\n<p>Polygon Labs said any Polygon PoS node that stayed on pre-hardfork Bor or Heimdall binaries past two August activation heights has already fallen out of canonical consensus. In practice, the stale node must upgrade and catch up before it can follow the network\u2019s accepted history again.<\/p>\n<p>The company\u2019s Aug. 27 security review described a client-compatibility consequence. Polygon said it had not observed mainnet disruption from Austin and framed the disclosed changes as proactive fixes.<\/p>\n<p>Bor is Polygon PoS\u2019s execution client, while Heimdall handles consensus and checkpointing. Bor versions earlier than v2.10.0 are incompatible after Austin activated at mainnet block 91,949,700, a cutoff that applies to all Bor node roles.<\/p>\n<p>Heimdall validators and full nodes need v0.11.0 after Kyoto activated at height 51,533,000. Polygon\u2019s Heimdall release notice dates that mainnet activation to Aug. 18 at 10:10:31 UTC.<\/p>\n<h2>Austin and Kyoto addressed separate client risks<\/h2>\n<figure id=\"attachment_558804\" aria-describedby=\"caption-attachment-558804\" style=\"width: 720px\" class=\"wp-caption aligncenter\"><img fetchpriority=\"high\" decoding=\"async\" class=\"wp-image-558804\" src=\"https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa.png\" alt=\"Comparison of Polygon PoS Austin and Kyoto hardfork versions, activation heights, affected nodes, security fixes and stale-node recovery\" width=\"720\" height=\"1080\" srcset=\"https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa.png 1024w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-200x300.png 200w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-683x1024.png 683w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-768x1152.png 768w\" sizes=\"(max-width: 720px) 100vw, 720px\"\/><img decoding=\"async\" class=\"lazyload wp-image-558804\" src=\"https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa.png\" alt=\"Comparison of Polygon PoS Austin and Kyoto hardfork versions, activation heights, affected nodes, security fixes and stale-node recovery\" width=\"720\" height=\"1080\" srcset=\"https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa.png 1024w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-200x300.png 200w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-683x1024.png 683w, https:\/\/cryptoslate.com\/wp-content\/uploads\/2026\/08\/exec-c12b333f-e9b7-45ac-9cfd-d08a0213f0fa-768x1152.png 768w\" data-sizes=\"(max-width: 720px) 100vw, 720px\"\/><figcaption id=\"caption-attachment-558804\" class=\"wp-caption-text\">Infographic compares Polygon PoS security hardforks Austin\/Bor and Kyoto\/Heimdall, outlining software requirements, fixes, and stale-node consequences.<\/figcaption><\/figure>\n<p>Austin capped the gas consumed while Bor processes state-sync events from L1-to-L2 bridge deposits. Those events execute contract code and precompiles, but their gas use was not previously counted against a fixed block-level ceiling.<\/p>\n<p>Enough events, or one sufficiently costly event, could make block processing slow enough to stall the chain transiently.<\/p>\n<aside id=\"cs-inline-newsletter-1\" class=\"cs-inline-newsletter\" data-inline-newsletter=\"\" data-newsletter-placement=\"article-midpoint\" data-newsletter-pending-label=\"Joining\u2026\" data-newsletter-pending-status=\"Joining the Daily Brief\u2026\" data-newsletter-email-required-message=\"Before sending, please provide your email address.\" aria-labelledby=\"cs-inline-newsletter-1-title\" aria-describedby=\"cs-inline-newsletter-1-copy\">\n<div class=\"cs-inline-newsletter__inner\">\n<div class=\"cs-inline-newsletter__content\"> <span class=\"cs-inline-newsletter__eyebrow\"> <i class=\"fa-regular fa-envelope\" aria-hidden=\"true\"\/> The Daily Brief <\/span><\/p>\n<h2 id=\"cs-inline-newsletter-1-title\" class=\"cs-inline-newsletter__title\">The signal, before the noise.<\/h2>\n<p id=\"cs-inline-newsletter-1-copy\" class=\"cs-inline-newsletter__copy\">Start your day with the crypto stories moving markets, decoded by CryptoSlate\u2019s editors.<\/p>\n<\/div>\n<div class=\"cs-inline-newsletter__form-shell\">\n<p class=\"cs-inline-newsletter__form-heading\">One email. Everything that matters.<\/p>\n<p id=\"cs-inline-newsletter-1-privacy\" class=\"cs-inline-newsletter__privacy\">Free to join. Unsubscribe any time.<\/p>\n<p> <i class=\"fa-regular fa-circle-xmark\" aria-hidden=\"true\"\/> <span>Whoops, looks like there was a problem. Please try again.<\/span><\/p>\n<p> <i class=\"fa-regular fa-circle-check\" aria-hidden=\"true\"\/> <span><strong>You\u2019re on the list.<\/strong> Your next Daily Brief is on its way.<\/span><\/p>\n<\/div>\n<\/div>\n<\/aside>\n<p>The second weakness sat in Bor\u2019s <code>TxDependency<\/code> extra-data field, a hint used for parallel execution. Because the producer-supplied field had no size limit, a block producer could place an arbitrarily large blob in an otherwise valid sibling block and crash peers that tried to process it.<\/p>\n<p>Austin removed the field from the wire format, and Polygon classified both weaknesses as resource-exhaustion risks.<\/p>\n<p>The public Bor v2.10.0 release records Austin\u2019s mainnet and Amoy activation blocks. GitHub showed v2.10.1 as the latest Bor release when checked Aug. 28, while v2.10.0 or later provides Austin compatibility.<\/p>\n<p>Operationally, one Austin path threatened delayed block processing, while the other could terminate peers receiving a producer\u2019s oversized data field.<\/p>\n<div class=\"cs-article-embed\">\n<p> <span class=\"cs-article-embed__related-reading\">Related Reading<\/span><\/p>\n<h3 class=\"cs-article-embed__title\">Polygon suffers hour-long RPC disruption affecting block production; Heimdall hotfix to blame<\/h3>\n<\/p>\n<p> <span class=\"cs-article-embed__arrow\" aria-hidden=\"true\"> <i class=\"fa-light fa-arrow-up-right\"\/> <\/span> <\/div>\n<p>Kyoto\u2019s highest-severity fix targets deeply nested <code>google.protobuf.Any<\/code> messages. A sender could cheaply construct one transaction that forced every validator to spend heavily on decoding. The hardfork added a byte-level nesting check at both mempool admission and block-proposal processing, keeping those paths consistent.<\/p>\n<p>It separately capped fee-coin lists before an O(n) validation scan, and Heimdall\u2019s integration permits one fee coin.<\/p>\n<p>Other Kyoto changes address distinct edge cases. They normalize checkpoint signature recovery bytes so a valid signature cannot fail recovery on Ethereum and stall anchoring, make repeated producer-downtime messages idempotent, bind milestone-range votes to the signed parent hash, and prevent a failed future-span creation from blocking milestone commitment.<\/p>\n<p>Replay keys for topup, clerk, and stake events were also made injective for out-of-range log indexes so distinct layer-1 events cannot silently shadow each other.<\/p>\n<p>Both hardforks are plain binary upgrades with no state migration or genesis change, and nodes that had not diverged require no resync.<\/p>\n<p>Operators already past the relevant height on an older client should install the applicable release, roll back to a pre-hardfork point if needed, and resync under Polygon\u2019s guidance.<\/p>\n<\/div>\n<p>Adoption,Featured,Governance,Technology,ethereumethereum#Polygon #Labs #issues #urgent #client #upgrade #notice #Austin #Kyoto #hardforks1787997014<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Polygon Labs said any Polygon PoS node that stayed on pre-hardfork Bor or Heimdall binaries past two August activation heights has already fallen out of canonical consensus. In practice, the stale node must upgrade and catch up before it can follow the network\u2019s accepted history again. The company\u2019s Aug. 27 security review described a client-compatibility<\/p>\n","protected":false},"author":1,"featured_media":12539,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[6580,5802,31,6582,356,6581,240,3773,1018,1300,1896],"class_list":["post-12538","post","type-post","status-publish","format-standard","has-post-thumbnail","category-ethereum","tag-austin","tag-client","tag-ethereum","tag-hardforks","tag-issues","tag-kyoto","tag-labs","tag-notice","tag-polygon","tag-upgrade","tag-urgent"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v26.6 (Yoast SEO v26.6) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Polygon Labs issues urgent client upgrade notice following Austin and Kyoto hardforks - Crypto News: Latest Cryptocurrency News and Analysis<\/title>\n<meta name=\"description\" content=\"The Polygon upgrades closed separate block-stall, peer-crash, and validator-work risks, leaving nodes on older binaries outside canonical consensus.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/cryptonews.uk.com\/?p=12538\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Polygon Labs issues urgent client upgrade notice following Austin and Kyoto hardforks\" \/>\n<meta property=\"og:description\" content=\"The Polygon upgrades closed separate block-stall, peer-crash, and validator-work risks, leaving nodes on older binaries outside canonical consensus.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/cryptonews.uk.com\/?p=12538\" \/>\n<meta property=\"og:site_name\" content=\"Crypto News: Latest Cryptocurrency News and Analysis\" \/>\n<meta property=\"article:published_time\" content=\"2026-08-29T09:50:14+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/cryptonews.uk.com\/wp-content\/uploads\/2026\/08\/polygon-consensus-chain-break.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1280\" \/>\n\t<meta property=\"og:image:height\" content=\"720\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"\u884c\u653f\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"\u884c\u653f\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538\",\"url\":\"https:\/\/cryptonews.uk.com\/?p=12538\",\"name\":\"Polygon Labs issues urgent client upgrade notice following Austin and Kyoto hardforks - Crypto News: Latest Cryptocurrency News and Analysis\",\"isPartOf\":{\"@id\":\"https:\/\/cryptonews.uk.com\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538#primaryimage\"},\"image\":{\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538#primaryimage\"},\"thumbnailUrl\":\"https:\/\/cryptonews.uk.com\/wp-content\/uploads\/2026\/08\/polygon-consensus-chain-break.jpg\",\"datePublished\":\"2026-08-29T09:50:14+00:00\",\"author\":{\"@id\":\"https:\/\/cryptonews.uk.com\/#\/schema\/person\/822778c5844e0d16d43dce6630f4f1bf\"},\"description\":\"The Polygon upgrades closed separate block-stall, peer-crash, and validator-work risks, leaving nodes on older binaries outside canonical consensus.\",\"breadcrumb\":{\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/cryptonews.uk.com\/?p=12538\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538#primaryimage\",\"url\":\"https:\/\/cryptonews.uk.com\/wp-content\/uploads\/2026\/08\/polygon-consensus-chain-break.jpg\",\"contentUrl\":\"https:\/\/cryptonews.uk.com\/wp-content\/uploads\/2026\/08\/polygon-consensus-chain-break.jpg\",\"width\":1280,\"height\":720},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/cryptonews.uk.com\/?p=12538#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/cryptonews.uk.com\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Polygon Labs issues urgent client upgrade notice following Austin and Kyoto hardforks\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/cryptonews.uk.com\/#website\",\"url\":\"https:\/\/cryptonews.uk.com\/\",\"name\":\"Crypto News: Latest Cryptocurrency News and Analysis\",\"description\":\"Latest Crypto &amp; 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