diff --git a/src/controllers/DonationController.ts b/src/controllers/DonationController.ts
index e19c0b9..b7dc153 100644
--- a/src/controllers/DonationController.ts
+++ b/src/controllers/DonationController.ts
@@ -1,11 +1,12 @@
-import { Authorized, Body, Delete, Get, JsonController, OnUndefined, Param, Post, QueryParam } from 'routing-controllers';
+import { Authorized, Body, Delete, Get, JsonController, OnUndefined, Param, Post, Put, QueryParam } from 'routing-controllers';
 import { OpenAPI, ResponseSchema } from 'routing-controllers-openapi';
 import { getConnectionManager, Repository } from 'typeorm';
-import { DonationNotFoundError } from '../errors/DonationErrors';
+import { DonationIdsNotMatchingError, DonationNotFoundError } from '../errors/DonationErrors';
 import { DonorNotFoundError } from '../errors/DonorErrors';
 import { RunnerNotFoundError } from '../errors/RunnerErrors';
 import { CreateDistanceDonation } from '../models/actions/create/CreateDistanceDonation';
 import { CreateFixedDonation } from '../models/actions/create/CreateFixedDonation';
+import { UpdateFixedDonation } from '../models/actions/update/UpdateFixedDonation';
 import { DistanceDonation } from '../models/entities/DistanceDonation';
 import { Donation } from '../models/entities/Donation';
 import { FixedDonation } from '../models/entities/FixedDonation';
@@ -79,28 +80,28 @@ export class DonationController {
 		return (await this.donationRepository.findOne({ id: donation.id }, { relations: ['runner', 'donor', 'runner.scans', 'runner.scans.track'] })).toResponse();
 	}
 
-	// @Put('/:id')
-	// @Authorized("SCAN:UPDATE")
-	// @ResponseSchema(ResponseScan)
-	// @ResponseSchema(DonationNotFoundError, { statusCode: 404 })
-	// @ResponseSchema(DonorNotFoundError, { statusCode: 404 })
-	// @ResponseSchema(RunnerNotFoundError, { statusCode: 404 })
-	// @ResponseSchema(DonationIdsNotMatchingError, { statusCode: 406 })
-	// @OpenAPI({ description: "Update the fixed donation (not distance donation - use /donations/fixed instead) whose id you provided. <br> Please remember that ids can't be changed and amounts must be positive." })
-	// async putFixed(@Param('id') id: number, @Body({ validate: true }) donation: UpdateDistanceDonation) {
-	// 	let oldDonation = await this.fixedDonationRepository.findOne({ id: id });
+	@Put('/:id')
+	@Authorized("DONATION:UPDATE")
+	@ResponseSchema(ResponseDonation)
+	@ResponseSchema(DonationNotFoundError, { statusCode: 404 })
+	@ResponseSchema(DonorNotFoundError, { statusCode: 404 })
+	@ResponseSchema(RunnerNotFoundError, { statusCode: 404 })
+	@ResponseSchema(DonationIdsNotMatchingError, { statusCode: 406 })
+	@OpenAPI({ description: "Update the fixed donation (not distance donation - use /donations/fixed instead) whose id you provided. <br> Please remember that ids can't be changed and amounts must be positive." })
+	async putFixed(@Param('id') id: number, @Body({ validate: true }) donation: UpdateFixedDonation) {
+		let oldDonation = await this.fixedDonationRepository.findOne({ id: id });
 
-	// 	if (!oldDonation) {
-	// 		throw new ScanNotFoundError();
-	// 	}
+		if (!oldDonation) {
+			throw new DonationNotFoundError();
+		}
 
-	// 	if (oldDonation.id != donation.id) {
-	// 		throw new ScanIdsNotMatchingError();
-	// 	}
+		if (oldDonation.id != donation.id) {
+			throw new DonationIdsNotMatchingError();
+		}
 
-	// 	await this.fixedDonationRepository.save(await donation.update(oldDonation));
-	// 	return (await this.donationRepository.findOne({ id: donation.id }, { relations: ['donor'] })).toResponse();
-	// }
+		await this.fixedDonationRepository.save(await donation.update(oldDonation));
+		return (await this.donationRepository.findOne({ id: donation.id }, { relations: ['donor'] })).toResponse();
+	}
 
 	// @Put('/trackscans/:id')
 	// @Authorized("SCAN:UPDATE")
diff --git a/src/models/actions/update/UpdateDonation.ts b/src/models/actions/update/UpdateDonation.ts
new file mode 100644
index 0000000..7f10f97
--- /dev/null
+++ b/src/models/actions/update/UpdateDonation.ts
@@ -0,0 +1,41 @@
+import { IsInt, IsPositive } from 'class-validator';
+import { getConnection } from 'typeorm';
+import { DonorNotFoundError } from '../../../errors/DonorErrors';
+import { Donation } from '../../entities/Donation';
+import { Donor } from '../../entities/Donor';
+
+/**
+ * This class is used to update a Donation entity (via put request).
+ */
+export abstract class UpdateDonation {
+    /**
+     * The updated donation's id.
+     * This shouldn't have changed but it is here in case anyone ever wants to enable id changes (whyever they would want to).
+     */
+    @IsInt()
+    id: number;
+
+    /**
+     * The updated donation's associated donor.
+     * This is important to link donations to donors.
+     */
+    @IsInt()
+    @IsPositive()
+    donor: number;
+
+    /**
+     * Creates a new Donation entity from this.
+     */
+    public abstract update(donation: Donation): Promise<Donation>;
+
+    /**
+     * Gets a donor based on the donor id provided via this.donor.
+     */
+    public async getDonor(): Promise<Donor> {
+        const donor = await getConnection().getRepository(Donor).findOne({ id: this.donor });
+        if (!donor) {
+            throw new DonorNotFoundError();
+        }
+        return donor;
+    }
+}
\ No newline at end of file
diff --git a/src/models/actions/update/UpdateFixedDonation.ts b/src/models/actions/update/UpdateFixedDonation.ts
new file mode 100644
index 0000000..5e31068
--- /dev/null
+++ b/src/models/actions/update/UpdateFixedDonation.ts
@@ -0,0 +1,27 @@
+import { IsInt, IsPositive } from 'class-validator';
+import { FixedDonation } from '../../entities/FixedDonation';
+import { UpdateDonation } from './UpdateDonation';
+
+/**
+ * This class is used to update a FixedDonation entity (via put request).
+ */
+export class UpdateFixedDonation extends UpdateDonation {
+    /**
+     * The updated donation's amount.
+     * The unit is your currency's smallest unit (default: euro cent).
+     */
+    @IsInt()
+    @IsPositive()
+    amount: number;
+
+    /**
+     * Update a FixedDonation entity based on this.
+     * @param donation The donation that shall be updated.
+     */
+    public async update(donation: FixedDonation): Promise<FixedDonation> {
+        donation.amount = this.amount;
+        donation.donor = await this.getDonor();
+
+        return donation;
+    }
+}
\ No newline at end of file