{"record":{"id":"971dd21632dd6337","repo":"handlebars-lang/handlebars.js","slug":"template-was-precompiled-with-an-older-version-of","errorCode":null,"errorMessage":"Template was precompiled with an older version of Handlebars than the current runtime. Please update your precompiler to a newer version (${runtimeVersions}) or downgrade your runtime to an older version (${compilerVersions}).","messagePattern":"Template was precompiled with an older version of Handlebars than the current runtime\\. Please update your precompiler to a newer version \\((.+?)\\) or downgrade your runtime to an older version \\((.+?)\\)\\.","errorType":"exception","errorClass":"Exception","httpStatus":null,"severity":"error","filePath":"lib/handlebars/runtime.js","lineNumber":30,"sourceCode":"  createProtoAccessControl,\n  resultIsAllowed,\n} from './internal/proto-access.js';\n\nexport function checkRevision(compilerInfo) {\n  const compilerRevision = (compilerInfo && compilerInfo[0]) || 1,\n    currentRevision = COMPILER_REVISION;\n\n  if (\n    compilerRevision >= LAST_COMPATIBLE_COMPILER_REVISION &&\n    compilerRevision <= COMPILER_REVISION\n  ) {\n    return;\n  }\n\n  if (compilerRevision < LAST_COMPATIBLE_COMPILER_REVISION) {\n    const runtimeVersions = REVISION_CHANGES[currentRevision],\n      compilerVersions = REVISION_CHANGES[compilerRevision];\n    throw new Exception(\n      'Template was precompiled with an older version of Handlebars than the current runtime. ' +\n        'Please update your precompiler to a newer version (' +\n        runtimeVersions +\n        ') or downgrade your runtime to an older version (' +\n        compilerVersions +\n        ').'\n    );\n  } else {\n    // Use the embedded version info since the runtime doesn't know about this revision yet\n    throw new Exception(\n      'Template was precompiled with a newer version of Handlebars than the current runtime. ' +\n        'Please update your runtime to a newer version (' +\n        compilerInfo[1] +\n        ').'\n    );\n  }\n}\n","sourceCodeStart":12,"sourceCodeEnd":48,"githubUrl":"https://github.com/handlebars-lang/handlebars.js/blob/13a7a679910d2adbfe7f6fad61ce8f98426b0378/lib/handlebars/runtime.js#L12-L48","documentation":"Precompiled Handlebars templates embed a compiler revision (COMPILER_REVISION). At load time the runtime's `checkRevision` compares the template's revision against the runtime's revision and the minimum compatible revision (LAST_COMPATIBLE_COMPILER_REVISION). If the template's revision is older than the minimum the runtime supports, it throws this Exception because the template data format can no longer be trusted.","triggerScenarios":"`checkRevision` is called during template load and `compilerRevision < LAST_COMPATIBLE_COMPILER_REVISION`, i.e. a template precompiled by a Handlebars compiler old enough that the current runtime no longer accepts its format.","commonSituations":"Upgrading the handlebars runtime dependency without re-running the precompiler; templates checked into the repo were generated years ago by handlebars 1.x/2.x while the app now runs handlebars 4.x; a build cache served stale precompiled template files.","solutions":["Re-precompile all templates with the current handlebars version (`handlebars templates/ -f compiled.js`) so COMPILER_REVISION matches the runtime","If re-precompiling is impossible, downgrade the handlebars runtime package to a version within the range printed in the error message","Clear build/CI caches so freshly compiled templates are deployed","Pin the compiler and runtime to the same handlebars version in package.json/lockfile"],"exampleFix":"// before: stale precompiled template from old compiler\n// templates/compiled.js generated by handlebars 1.3, runtime is 4.7\nimport compiled from './templates/compiled.js';\n\n// after: regenerate with the installed compiler version\n// npx handlebars templates/ -f templates/compiled.js\nimport compiled from './templates/compiled.js';","handlingStrategy":"validation","validationCode":"import compiledSpec from './templates/compiled.js';\nimport Handlebars from 'handlebars/runtime';\n\nfunction assertTemplateCompatible(spec) {\n  const compilerRevision = spec.compiler?.[0];\n  if (compilerRevision < 7) { // LAST_COMPATIBLE_COMPILER_REVISION for hb 4.x\n    throw new Error('Template precompiled by unsupported old Handlebars; recompile it');\n  }\n}\nassertTemplateCompatible(compiledSpec);\nHandlebars.template(compiledSpec);","typeGuard":"function isCompatibleSpec(spec) {\n  return spec && typeof spec === 'object' &&\n    Array.isArray(spec.compiler) && spec.compiler[0] >= 7;\n}","tryCatchPattern":"try {\n  const tmpl = Handlebars.template(compiledSpec);\n} catch (e) {\n  if (e.message.includes('precompiled with an older version')) {\n    throw new Error('Re-run the precompiler: npx handlebars templates/ -f templates/compiled.js');\n  }\n  throw e;\n}","preventionTips":["Generate precompiled templates in the same build step that installs/locks handlebars, never commit stale ones","Pin one handlebars version for both compiler (devDependency) and runtime (dependency)","Invalidate build caches whenever the handlebars version changes","Add a CI check that asserts compiledSpec.compiler matches the runtime revision"],"tags":["handlebars","precompiled-template","version-mismatch","runtime"],"backgroundTag":"precompiled-template-version-mismatch","analyzedSha":"13a7a679910d2adbfe7f6fad61ce8f98426b0378","analyzedAt":"2026-09-02T20:25:07.518Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-10T02:17:09.455Z"}