diff --git a/ui/src/lib/users.js b/ui/src/lib/users.js
index ab10e86..4b82cde 100644
--- a/ui/src/lib/users.js
+++ b/ui/src/lib/users.js
@@ -19,6 +19,18 @@ export async function getUsers(promo, group) {
   }
 }
 
+export async function anonOldAccounts() {
+  const res = await fetch('api/users', {
+    method: 'PATCH',
+    headers: {'Accept': 'application/json'},
+  });
+  if (res.status == 200) {
+    return await res.json()
+  } else {
+    throw new Error((await res.json()).errmsg);
+  }
+}
+
 export class User {
   constructor(res) {
     if (res) {
diff --git a/ui/src/routes/users/+page.svelte b/ui/src/routes/users/+page.svelte
index 91d895c..fd195a0 100644
--- a/ui/src/routes/users/+page.svelte
+++ b/ui/src/routes/users/+page.svelte
@@ -3,28 +3,45 @@
 
  import { user } from '$lib/stores/user';
  import DateFormat from '$lib/components/DateFormat.svelte';
- import { getUsers, getPromos } from '$lib/users';
+ import { anonOldAccounts, getUsers, getPromos } from '$lib/users';
 
  function showUser(user) {
      goto(`users/${user.id}`)
  }
 
+ let usersP = getUsers();
+ function refreshUsers() {
+     usersP = getUsers();
+ }
+
+ function askAnon() {
+     if (confirm("Ceci va anonymiser tous les comptes des étudiants avant " + ($user.current_promo - 1) + ". Voulez-vous continuer ?"))
+         anonOldAccounts().then(refreshUsers);
+ }
+
  let filterPromo = "";
 </script>
 
 {#if $user && $user.is_admin}
+    <button
+        class="btn btn-danger ms-2 float-end"
+        on:click={askAnon}
+    >
+        <i class="bi bi-back"></i>
+        Anonymiser vieux comptes
+    </button>
     <a
         href="auth/gitlabcri?next={window.location.pathname}"
-        class="btn btn-primary float-end"
+        class="btn btn-primary float-end ms-2"
     >
         <i class="bi bi-link-45deg"></i>
         OAuth GitLab
     </a>
-    <a href="grades/{filterPromo}" class="btn btn-success me-1 float-end" title="Notes">
+    <a href="grades/{filterPromo}" class="btn btn-success ms-2 float-end" title="Notes">
         <i class="bi bi-files"></i>
     </a>
     {#await getPromos() then promos}
-        <div class="float-end me-2">
+        <div class="float-end ms-2">
             <select class="form-select" bind:value={filterPromo}>
                 <option value="">-</option>
                 {#each promos as promo, pid (pid)}
@@ -38,7 +55,7 @@
   Étudiants
 </h2>
 
-{#await getUsers()}
+{#await usersP}
     <div class="text-center">
         <div class="spinner-border text-danger mx-3" role="status"></div>
         <span>Chargement des &eacute;tudiants &hellip;</span>
diff --git a/users.go b/users.go
index 26dcfe3..f15cf4b 100644
--- a/users.go
+++ b/users.go
@@ -81,6 +81,38 @@ func declareAPIAdminUsersRoutes(router *gin.RouterGroup) {
 		c.JSON(http.StatusOK, ret)
 	})
 
+	// Anonymize old accounts
+	router.PATCH("/users", func(c *gin.Context) {
+		users, err := getUsers()
+		if err != nil {
+			log.Println("Unable to getUsers:", err)
+			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to retrieve users. Please try again later."})
+			return
+		}
+
+		var filterPromo *uint64
+		if c.Query("promo") != "" {
+			fPromo, err := strconv.ParseUint(c.Query("promo"), 10, 64)
+			if err != nil {
+				c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": fmt.Sprintf("Unable to parse promo: %s", err.Error())})
+				return
+			}
+			filterPromo = &fPromo
+		}
+
+		for _, u := range users {
+			if (filterPromo == nil && u.Promo < currentPromo-1) || (filterPromo != nil && uint(*filterPromo) == u.Promo) {
+				u.Anonymize()
+				_, err = u.Update()
+				if err != nil {
+					log.Printf("Unable to anonymize %s: %s", u.Login, err.Error())
+				}
+			}
+		}
+
+		c.JSON(http.StatusOK, true)
+	})
+
 	usersRoutes := router.Group("/users/:uid")
 	usersRoutes.Use(userHandler)
 
@@ -247,6 +279,13 @@ func NewUser(login string, email string, firstname string, lastname string, prom
 	}
 }
 
+func (u *User) Anonymize() {
+	u.Login = fmt.Sprintf("Anonyme #%d", u.Id)
+	u.Email = fmt.Sprintf("anonyme-%d@non-existant.email", u.Id)
+	u.Firstname = "Arnaud"
+	u.Lastname = "Nimes"
+}
+
 func (u User) Update() (int64, error) {
 	if res, err := DBExec("UPDATE users SET login = ?, email = ?, firstname = ?, lastname = ?, time = ?, promo = ?, groups = ? WHERE id_user = ?", u.Login, u.Email, u.Firstname, u.Lastname, u.Time, u.Promo, u.Groups, u.Id); err != nil {
 		return 0, err