diff --git a/lib/legacyMessages/helpers.js b/lib/legacyMessages/helpers.js
new file mode 100644
index 00000000..50754413
--- /dev/null
+++ b/lib/legacyMessages/helpers.js
@@ -0,0 +1,158 @@
+import { encryptMessage, decryptMessageLegacy } from 'pmcrypto';
+// import { fromUnixTime } from 'date-fns';
+
+import { chunk } from '../helpers/array';
+import { wait } from '../helpers/promise';
+import { noop } from '../helpers/function';
+
+const fromUnixTime = (Time = 0) => new Date(Time * 1000);
+const LABEL_LEGACY_MESSAGE = '11';
+const QUERY_LEGACY_MESSAGES_MAX_PAGESIZE = 150;
+const UPDATE_BODY_SUCESS_CODE = 1000;
+const LEGACY_MESSAGES_CHUNK_SIZE = 5; // how many messages we want to decrypt and encrypt simultaneously
+const RELAX_TIME = 5 * 1000; // 5s . Time to wait (for other operations) after a batch of legacy messages has been migrated
+
+/**
+ * Given a list of legacy message IDs, fetch, decrypt, re-encrypt and send them to API
+ * @param {Array<String>} messageIDs        List of IDs of legacy messages
+ * @param {AbortController.signal} signal   { aborted: true/false }
+ * @param {Function} obj.getMessage         Retrive message from database by ID
+ * @param {Function} obj.updateBody         Replace body of a message identified by ID
+ * @param {Function} obj.getPrivateKeys     Get privateKeys corresponding to an address ID
+ * @param {Function} obj.onError
+ *
+ * @return {Object}                         { noneMigratedInBatch: false is some message from the batch is succesfully migrated. True otherwise }
+ *
+ * @dev    The keys returned by getPrivateKeys must have the method toPublic()
+ */
+const clearSome = async (messageIDs = [], { signal, getMessage, updateBody, getPrivateKeys, onError = noop }) => {
+    if (!messageIDs.length) {
+        return;
+    }
+
+    let noneMigratedInBatch = true;
+    await Promise.all(
+        messageIDs.map(async (ID) => {
+            try {
+                if (signal.aborted) {
+                    return;
+                }
+
+                // Get message and private keys
+                const {
+                    data: { Message: message = {} },
+                } = await getMessage(ID);
+                const { Time, Body, AddressID } = message;
+                const privateKeys = await getPrivateKeys(AddressID);
+
+                if (signal.aborted) {
+                    return;
+                }
+
+                // Decrypt message
+                const { data } = await decryptMessageLegacy({
+                    message: Body,
+                    messageDate: fromUnixTime(Time),
+                    privateKeys,
+                });
+
+                if (signal.aborted) {
+                    return;
+                }
+
+                // Re-encrypt message body. Use the primary key (first in the array) for re-encryption
+                const publicKeys = [privateKeys[0].toPublic()];
+                const { data: newBody } = await encryptMessage({
+                    data,
+                    publicKeys,
+                    format: 'utf8',
+                    compression: true,
+                });
+
+                if (signal.aborted) {
+                    return;
+                }
+                // Send re-encrypted message to API
+                const { Code } = await updateBody({ ID, Body: newBody });
+                if (Code === UPDATE_BODY_SUCESS_CODE) {
+                    noneMigratedInBatch = false;
+                }
+                return;
+            } catch (e) {
+                e.message = `Error migrating legacy message with messageID ${ID}. ${e.message}`;
+                onError(e);
+            }
+        })
+    );
+
+    return { noneMigratedInBatch };
+};
+
+/**
+ * Fetch legacy messages, re-encrypt and send them to API
+ * @param {AbortController.signal} signal   { aborted: true/false }
+ * @param {Number} page                     Legacy messages query parameter
+ * @param {Function} obj.queryMessages      Retrive legacy messages from database
+ * @param {Function} obj.getMessage         Retrive message from database by ID
+ * @param {Function} obj.updateBody         Replace body of a message identified by ID
+ * @param {Function} obj.getPrivateKeys     Get privateKeys corresponding to an address ID
+ * @param {Function} obj.onError
+ *
+ * @dev    The keys returned by getPrivateKeys must have the method toPublic()
+ */
+export const clearAll = async ({
+    signal,
+    page = 0,
+    queryMessages,
+    getMessage,
+    updateBody,
+    getPrivateKeys,
+    onError,
+}) => {
+    if (signal.aborted) {
+        return;
+    }
+
+    const { data = {} } = await queryMessages({
+        LabelID: [LABEL_LEGACY_MESSAGE],
+        Page: page,
+        PageSize: QUERY_LEGACY_MESSAGES_MAX_PAGESIZE,
+    });
+    const { Messages = [] } = data;
+
+    if (!Messages.length) {
+        return;
+    }
+
+    // proceed in batches of messages, not to burn user's machine decrypting and re-encrypting
+    const messageIDs = chunk(
+        Messages.map(({ ID }) => ID),
+        LEGACY_MESSAGES_CHUNK_SIZE
+    );
+    let noneMigrated = true;
+    for (let i = 0; i < messageIDs.length; i++) {
+        const { noneMigratedInBatch } = await clearSome(messageIDs[i], {
+            signal,
+            getMessage,
+            updateBody,
+            getPrivateKeys,
+            onError,
+        });
+        noneMigrated = noneMigrated && noneMigratedInBatch;
+        if (!signal.aborted) {
+            await wait(RELAX_TIME);
+        }
+    }
+
+    // updateBody removes legacy label only if update successful
+    // change page accordingly
+    return clearAll({
+        signal,
+        page: page + noneMigrated,
+        queryMessages,
+        getMessage,
+        updateBody,
+        getPrivateKeys,
+        onError,
+    });
+};