diff --git a/packages/ruleset-migrator/src/__tests__/ruleset.test.ts b/packages/ruleset-migrator/src/__tests__/ruleset.test.ts
index 4f41b3d7a..71d7a8a01 100644
--- a/packages/ruleset-migrator/src/__tests__/ruleset.test.ts
+++ b/packages/ruleset-migrator/src/__tests__/ruleset.test.ts
@@ -149,16 +149,18 @@ describe('migrator', () => {
 `);
   });
 
-  describe('error handling', () => {
-    it('given unknown format, should throw', async () => {
-      await vol.promises.writeFile(path.join(cwd, 'unknown-format.json'), `{ "formats": ["json-schema-draft-2"] }`);
-      await expect(
-        migrateRuleset(path.join(cwd, 'unknown-format.json'), {
-          format: 'esm',
-          fs: vol as any,
-        }),
-      ).rejects.toThrow('Invalid ruleset provided');
-    });
+  it('given an unknown format, should not throw', async () => {
+    await vol.promises.writeFile(path.join(cwd, 'unknown-format.json'), `{ "formats": ["json-schema-draft-2"] }`);
+    await expect(
+      migrateRuleset(path.join(cwd, 'unknown-format.json'), {
+        format: 'esm',
+        fs: vol as any,
+      }),
+    ).resolves.toEqual(`import {jsonSchemaDraft2} from "@stoplight/spectral-formats";
+export default {
+  "formats": [jsonSchemaDraft2]
+};
+`);
   });
 
   it('should follow links correctly', async () => {
diff --git a/packages/ruleset-migrator/src/transformers/formats.ts b/packages/ruleset-migrator/src/transformers/formats.ts
index decef6352..9a004cdc8 100644
--- a/packages/ruleset-migrator/src/transformers/formats.ts
+++ b/packages/ruleset-migrator/src/transformers/formats.ts
@@ -2,15 +2,36 @@ import { builders as b, namedTypes } from 'ast-types';
 import { Transformer, TransformerCtx } from '../types';
 import { assertArray, assertString } from '../validation';
 
-import schema from '../validation/schema';
-
 const ALIASES: Record<string, string> = {
   'json-schema-2019-09': 'json-schema-draft-2019-09',
   'json-schema-2020-12': 'json-schema-draft-2020-12',
 };
 
+const FORMATS = [
+  'oas2',
+  'oas3',
+  'oas3.0',
+  'oas3.1',
+  'asyncapi2',
+  'json-schema',
+  'json-schema-loose',
+  'json-schema-draft4',
+  'json-schema-draft6',
+  'json-schema-draft7',
+  'json-schema-draft-2019-09',
+  'json-schema-2019-09',
+  'json-schema-draft-2020-12',
+  'json-schema-2020-12',
+];
+
+function safeFormat(format: string): string {
+  return format
+    .replace(/\.|(?<=[0-9])-(?=[0-9])/g, '_')
+    .replace(/-([0-9a-z])/g, (match, char) => String(char).toUpperCase());
+}
+
 const REPLACEMENTS = Object.fromEntries(
-  schema.properties.formats.items.enum.map(format => [
+  FORMATS.map(format => [
     format,
     (ALIASES[format] ?? format)
       .replace(/\.|(?<=[0-9])-(?=[0-9])/g, '_')
@@ -26,7 +47,7 @@ function transform(input: unknown, ctx: TransformerCtx): namedTypes.ArrayExpress
       new Set(
         input.map(format => {
           assertString(format);
-          return ctx.tree.addImport(REPLACEMENTS[format], '@stoplight/spectral-formats');
+          return ctx.tree.addImport(REPLACEMENTS[format] ?? safeFormat(format), '@stoplight/spectral-formats');
         }),
       ),
     ),
diff --git a/packages/ruleset-migrator/src/validation/schema.ts b/packages/ruleset-migrator/src/validation/schema.ts
index fa80ef69f..6df09a0cc 100644
--- a/packages/ruleset-migrator/src/validation/schema.ts
+++ b/packages/ruleset-migrator/src/validation/schema.ts
@@ -6,44 +6,6 @@ const schema = {
   properties: {
     aliases: {
       type: 'object',
-      additionalProperties: {
-        oneOf: [
-          {
-            type: 'array',
-            items: {
-              type: 'string',
-            },
-          },
-          {
-            type: 'object',
-            properties: {
-              description: {
-                type: 'string',
-              },
-              targets: {
-                type: 'array',
-                minItems: 1,
-                items: {
-                  type: 'object',
-                  properties: {
-                    formats: {
-                      $ref: '#/properties/formats',
-                    },
-                    given: {
-                      type: 'array',
-                      items: {
-                        type: 'string',
-                      },
-                    },
-                  },
-                  required: ['formats', 'given'],
-                },
-              },
-            },
-            required: ['targets'],
-          },
-        ],
-      },
     },
     except: {
       type: 'object',
@@ -85,25 +47,8 @@ const schema = {
     },
     formats: {
       type: 'array',
-      minItems: 1,
       items: {
         type: 'string',
-        enum: [
-          'oas2',
-          'oas3',
-          'oas3.0',
-          'oas3.1',
-          'asyncapi2',
-          'json-schema',
-          'json-schema-loose',
-          'json-schema-draft4',
-          'json-schema-draft6',
-          'json-schema-draft7',
-          'json-schema-draft-2019-09',
-          'json-schema-2019-09',
-          'json-schema-draft-2020-12',
-          'json-schema-2020-12',
-        ],
       },
     },
     functions: {
diff --git a/packages/ruleset-migrator/src/validation/types.ts b/packages/ruleset-migrator/src/validation/types.ts
index 7234c9eb8..ae4aa3d12 100644
--- a/packages/ruleset-migrator/src/validation/types.ts
+++ b/packages/ruleset-migrator/src/validation/types.ts
@@ -2,166 +2,17 @@
 
 export interface Ruleset {
   aliases?: {
-    [k: string]:
-      | string[]
-      | {
-          description?: string;
-          targets: [
-            {
-              formats: [
-                (
-                  | 'oas2'
-                  | 'oas3'
-                  | 'oas3.0'
-                  | 'oas3.1'
-                  | 'asyncapi2'
-                  | 'json-schema'
-                  | 'json-schema-loose'
-                  | 'json-schema-draft4'
-                  | 'json-schema-draft6'
-                  | 'json-schema-draft7'
-                  | 'json-schema-draft-2019-09'
-                  | 'json-schema-2019-09'
-                  | 'json-schema-draft-2020-12'
-                  | 'json-schema-2020-12'
-                ),
-                ...(
-                  | 'oas2'
-                  | 'oas3'
-                  | 'oas3.0'
-                  | 'oas3.1'
-                  | 'asyncapi2'
-                  | 'json-schema'
-                  | 'json-schema-loose'
-                  | 'json-schema-draft4'
-                  | 'json-schema-draft6'
-                  | 'json-schema-draft7'
-                  | 'json-schema-draft-2019-09'
-                  | 'json-schema-2019-09'
-                  | 'json-schema-draft-2020-12'
-                  | 'json-schema-2020-12'
-                )[]
-              ];
-              given: string[];
-              [k: string]: unknown;
-            },
-            ...{
-              formats: [
-                (
-                  | 'oas2'
-                  | 'oas3'
-                  | 'oas3.0'
-                  | 'oas3.1'
-                  | 'asyncapi2'
-                  | 'json-schema'
-                  | 'json-schema-loose'
-                  | 'json-schema-draft4'
-                  | 'json-schema-draft6'
-                  | 'json-schema-draft7'
-                  | 'json-schema-draft-2019-09'
-                  | 'json-schema-2019-09'
-                  | 'json-schema-draft-2020-12'
-                  | 'json-schema-2020-12'
-                ),
-                ...(
-                  | 'oas2'
-                  | 'oas3'
-                  | 'oas3.0'
-                  | 'oas3.1'
-                  | 'asyncapi2'
-                  | 'json-schema'
-                  | 'json-schema-loose'
-                  | 'json-schema-draft4'
-                  | 'json-schema-draft6'
-                  | 'json-schema-draft7'
-                  | 'json-schema-draft-2019-09'
-                  | 'json-schema-2019-09'
-                  | 'json-schema-draft-2020-12'
-                  | 'json-schema-2020-12'
-                )[]
-              ];
-              given: string[];
-              [k: string]: unknown;
-            }[]
-          ];
-          [k: string]: unknown;
-        };
+    [k: string]: unknown;
   };
   except?: {
     [k: string]: string[];
   };
   extends?: string | (string | [string, 'all' | 'recommended' | 'off'])[];
-  formats?: [
-    (
-      | 'oas2'
-      | 'oas3'
-      | 'oas3.0'
-      | 'oas3.1'
-      | 'asyncapi2'
-      | 'json-schema'
-      | 'json-schema-loose'
-      | 'json-schema-draft4'
-      | 'json-schema-draft6'
-      | 'json-schema-draft7'
-      | 'json-schema-draft-2019-09'
-      | 'json-schema-2019-09'
-      | 'json-schema-draft-2020-12'
-      | 'json-schema-2020-12'
-    ),
-    ...(
-      | 'oas2'
-      | 'oas3'
-      | 'oas3.0'
-      | 'oas3.1'
-      | 'asyncapi2'
-      | 'json-schema'
-      | 'json-schema-loose'
-      | 'json-schema-draft4'
-      | 'json-schema-draft6'
-      | 'json-schema-draft7'
-      | 'json-schema-draft-2019-09'
-      | 'json-schema-2019-09'
-      | 'json-schema-draft-2020-12'
-      | 'json-schema-2020-12'
-    )[]
-  ];
+  formats?: string[];
   functions?: string[];
   functionsDir?: string;
   rules?: {
-    formats?: [
-      (
-        | 'oas2'
-        | 'oas3'
-        | 'oas3.0'
-        | 'oas3.1'
-        | 'asyncapi2'
-        | 'json-schema'
-        | 'json-schema-loose'
-        | 'json-schema-draft4'
-        | 'json-schema-draft6'
-        | 'json-schema-draft7'
-        | 'json-schema-draft-2019-09'
-        | 'json-schema-2019-09'
-        | 'json-schema-draft-2020-12'
-        | 'json-schema-2020-12'
-      ),
-      ...(
-        | 'oas2'
-        | 'oas3'
-        | 'oas3.0'
-        | 'oas3.1'
-        | 'asyncapi2'
-        | 'json-schema'
-        | 'json-schema-loose'
-        | 'json-schema-draft4'
-        | 'json-schema-draft6'
-        | 'json-schema-draft7'
-        | 'json-schema-draft-2019-09'
-        | 'json-schema-2019-09'
-        | 'json-schema-draft-2020-12'
-        | 'json-schema-2020-12'
-      )[]
-    ];
+    formats?: string[];
     [k: string]: unknown;
   };
   [k: string]: unknown;