diff --git a/keyserver/src/creators/message-creator.js b/keyserver/src/creators/message-creator.js
--- a/keyserver/src/creators/message-creator.js
+++ b/keyserver/src/creators/message-creator.js
@@ -26,6 +26,7 @@
   appendSQLArray,
   mergeOrConditions,
 } from '../database/database';
+import { getDBType } from '../database/db-config';
 import { fetchMessageInfoForLocalID } from '../fetchers/message-fetchers';
 import { fetchOtherSessionsForViewer } from '../fetchers/session-fetchers';
 import { fetchServerThreadInfos } from '../fetchers/thread-fetchers';
@@ -300,13 +301,15 @@
   `);
 
   const perUserInfo = new Map<string, UserThreadInfo>();
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
   for (const row of result) {
     const userID = row.user.toString();
     const threadID = row.thread.toString();
     const deviceToken = row.device_token;
     const focusedUser = !!row.focused_user;
-    const { platform, versions } = row;
+    const { platform } = row;
+    const versions =
+      dbType === 'mysql5.7' ? row.versions : JSON.parse(row.versions);
     let thisUserInfo = perUserInfo.get(userID);
     if (!thisUserInfo) {
       thisUserInfo = {
@@ -321,9 +324,14 @@
       // it once
       for (const subthread of subthreadPermissionsToCheck) {
         const isSubthreadMember = row[`subthread${subthread}_role`] > 0;
-        const permissions = row[`subthread${subthread}_permissions`];
+        const rawSubthreadPermissions =
+          row[`subthread${subthread}_permissions`];
+        const subthreadPermissions =
+          dbType === 'mysql5.7'
+            ? rawSubthreadPermissions
+            : JSON.parse(rawSubthreadPermissions);
         const canSeeSubthread = permissionLookup(
-          permissions,
+          subthreadPermissions,
           threadPermissions.KNOW_OF,
         );
         if (!canSeeSubthread) {
@@ -334,7 +342,7 @@
         // notification from the subthread
         if (
           !isSubthreadMember ||
-          !permissionLookup(permissions, threadPermissions.VISIBLE)
+          !permissionLookup(subthreadPermissions, threadPermissions.VISIBLE)
         ) {
           thisUserInfo.subthreadsCanNotify.add(subthread);
         }
diff --git a/keyserver/src/fetchers/entry-fetchers.js b/keyserver/src/fetchers/entry-fetchers.js
--- a/keyserver/src/fetchers/entry-fetchers.js
+++ b/keyserver/src/fetchers/entry-fetchers.js
@@ -29,6 +29,7 @@
   mergeAndConditions,
   mergeOrConditions,
 } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { SQLStatementType } from '../database/types';
 import type { Viewer } from '../session/viewer';
 import { creationString } from '../utils/idempotent';
@@ -154,7 +155,7 @@
     LEFT JOIN memberships m ON m.thread = t.id AND m.user = ${viewerID}
     WHERE e.id = ${entryID}
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
 
   if (result.length === 0) {
     return false;
@@ -172,7 +173,9 @@
     return false;
   }
 
-  return permissionLookup(row.permissions, permission);
+  const permissions =
+    dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions);
+  return permissionLookup(permissions, permission);
 }
 
 async function fetchEntryRevisionInfo(
diff --git a/keyserver/src/fetchers/message-fetchers.js b/keyserver/src/fetchers/message-fetchers.js
--- a/keyserver/src/fetchers/message-fetchers.js
+++ b/keyserver/src/fetchers/message-fetchers.js
@@ -31,6 +31,7 @@
   mergeOrConditions,
   mergeAndConditions,
 } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { SQLStatementType } from '../database/types';
 import type { PushInfo } from '../push/send';
 import type { Viewer } from '../session/viewer';
@@ -216,13 +217,22 @@
 }
 
 async function rawMessageInfoFromRows(
-  rows: $ReadOnlyArray<Object>,
+  rawRows: $ReadOnlyArray<Object>,
   viewer?: Viewer,
   derivedMessages: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
 ): Promise<?RawMessageInfo> {
+  let rows = rawRows;
+  const dbType = await getDBType();
+  if (dbType !== 'mysql5.7') {
+    rows = rawRows.map(row => ({
+      ...row,
+      subthread_permissions: JSON.parse(row.subthread_permissions),
+    }));
+  }
+
   const type = mostRecentRowType(rows);
   const messageSpec = messageSpecs[type];
 
diff --git a/keyserver/src/fetchers/report-fetchers.js b/keyserver/src/fetchers/report-fetchers.js
--- a/keyserver/src/fetchers/report-fetchers.js
+++ b/keyserver/src/fetchers/report-fetchers.js
@@ -11,6 +11,7 @@
 import { values } from 'lib/utils/objects';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { Viewer } from '../session/viewer';
 
 async function fetchErrorReportInfos(
@@ -30,18 +31,19 @@
     query.append(SQL`WHERE r.id < ${request.cursor} `);
   }
   query.append(SQL`ORDER BY r.id DESC`);
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
 
   const reports = [];
   const userInfos = {};
   for (const row of result) {
     const viewerID = row.user.toString();
-    let { platformDetails } = row.report;
+    const report = dbType === 'mysql5.7' ? row.report : JSON.parse(row.report);
+    let { platformDetails } = report;
     if (!platformDetails) {
       platformDetails = {
         platform: row.platform,
-        codeVersion: row.report.codeVersion,
-        stateVersion: row.report.stateVersion,
+        codeVersion: report.codeVersion,
+        stateVersion: report.stateVersion,
       };
     }
     reports.push({
@@ -74,22 +76,23 @@
     FROM reports
     WHERE id = ${id} AND type = ${reportTypes.ERROR}
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
   if (result.length === 0) {
     throw new ServerError('invalid_parameters');
   }
   const row = result[0];
 
-  const _persist = row.report.preloadedState._persist
-    ? row.report.preloadedState._persist
+  const report = dbType === 'mysql5.7' ? row.report : JSON.parse(row.report);
+  const _persist = report.preloadedState._persist
+    ? report.preloadedState._persist
     : {};
   const navState =
-    row.report.currentState && row.report.currentState.navState
-      ? row.report.currentState.navState
+    report.currentState && report.currentState.navState
+      ? report.currentState.navState
       : undefined;
   return {
     preloadedState: {
-      ...row.report.preloadedState,
+      ...report.preloadedState,
       _persist: {
         ..._persist,
         // Setting this to false disables redux-persist
@@ -98,7 +101,7 @@
       navState,
       frozen: true,
     },
-    payload: row.report.actions,
+    payload: report.actions,
   };
 }
 
diff --git a/keyserver/src/fetchers/role-fetchers.js b/keyserver/src/fetchers/role-fetchers.js
--- a/keyserver/src/fetchers/role-fetchers.js
+++ b/keyserver/src/fetchers/role-fetchers.js
@@ -3,6 +3,7 @@
 import type { RoleInfo } from 'lib/types/thread-types';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 
 async function fetchRoles(threadID: string): Promise<RoleInfo[]> {
   const query = SQL`
@@ -11,14 +12,15 @@
     LEFT JOIN threads t ON t.id = r.thread
     WHERE r.thread = ${threadID}
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
 
   const roles = [];
   for (const row of result) {
     roles.push({
       id: row.id.toString(),
       name: row.name,
-      permissions: row.permissions,
+      permissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
       isDefault: Boolean(row.is_default),
     });
   }
diff --git a/keyserver/src/fetchers/session-fetchers.js b/keyserver/src/fetchers/session-fetchers.js
--- a/keyserver/src/fetchers/session-fetchers.js
+++ b/keyserver/src/fetchers/session-fetchers.js
@@ -3,6 +3,7 @@
 import type { CalendarQuery } from 'lib/types/entry-types';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { Viewer } from '../session/viewer';
 
 type CalendarSessionResult = {
@@ -20,13 +21,13 @@
     WHERE m.thread = ${threadID} AND m.role > 0
       AND s.query IS NOT NULL
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
   const filters = [];
   for (const row of result) {
     filters.push({
       userID: row.user.toString(),
       session: row.id.toString(),
-      calendarQuery: row.query,
+      calendarQuery: dbType === 'mysql5.7' ? row.query : JSON.parse(row.query),
     });
   }
   return filters;
diff --git a/keyserver/src/fetchers/thread-fetchers.js b/keyserver/src/fetchers/thread-fetchers.js
--- a/keyserver/src/fetchers/thread-fetchers.js
+++ b/keyserver/src/fetchers/thread-fetchers.js
@@ -16,6 +16,7 @@
 import { ServerError } from 'lib/utils/errors';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { SQLStatementType } from '../database/types';
 import type { Viewer } from '../session/viewer';
 
@@ -47,7 +48,7 @@
   `
     .append(whereClause)
     .append(SQL` ORDER BY m.user ASC`);
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
 
   const threadInfos = {};
   for (const row of result) {
@@ -82,18 +83,27 @@
       threadInfos[threadID].roles[role] = {
         id: role,
         name: row.role_name,
-        permissions: JSON.parse(row.role_permissions),
+        permissions:
+          dbType === 'mysql5.7'
+            ? row.role_permissions
+            : JSON.parse(row.role_permissions),
         isDefault: role === row.default_role.toString(),
       };
     }
     if (row.user) {
       const userID = row.user.toString();
-      const allPermissions = getAllThreadPermissions(row.permissions, threadID);
+      const allPermissions = getAllThreadPermissions(
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
+        threadID,
+      );
       threadInfos[threadID].members.push({
         id: userID,
         permissions: allPermissions,
         role: row.role ? role : null,
-        subscription: row.subscription,
+        subscription:
+          dbType === 'mysql5.7'
+            ? row.subscription
+            : JSON.parse(row.subscription),
         unread: row.role ? !!row.unread : null,
         isSender: !!row.sender,
       });
diff --git a/keyserver/src/fetchers/thread-permission-fetchers.js b/keyserver/src/fetchers/thread-permission-fetchers.js
--- a/keyserver/src/fetchers/thread-permission-fetchers.js
+++ b/keyserver/src/fetchers/thread-permission-fetchers.js
@@ -19,6 +19,7 @@
 } from 'lib/types/thread-types';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { Viewer } from '../session/viewer';
 import { fetchThreadInfos } from './thread-fetchers';
 import { fetchKnownUserInfos } from './user-fetchers';
@@ -38,13 +39,13 @@
     FROM memberships
     WHERE thread = ${threadID} AND user = ${viewerID}
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
 
   if (result.length === 0) {
     return null;
   }
   const row = result[0];
-  return row.permissions;
+  return dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions);
 }
 
 function checkThreadPermission(
@@ -119,13 +120,19 @@
     }
   }
 
-  const [[result], disabledThreadIDs] = await Promise.all([
+  const [[result], dbType, disabledThreadIDs] = await Promise.all([
     dbQuery(query),
+    getDBType(),
     checkThreadsFrozen(viewer, permissionsToCheck, threadIDs),
   ]);
 
   return result
-    .map(row => ({ ...row, threadID: row.threadID.toString() }))
+    .map(row => ({
+      ...row,
+      threadID: row.threadID.toString(),
+      permissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
+    }))
     .filter(
       row =>
         isThreadValid(row.permissions, row.role, checks) &&
@@ -236,9 +243,13 @@
       FROM memberships
       WHERE thread = ${params.parentThreadID} AND user IN (${allCandidates})
     `;
-    const [result] = await dbQuery(parentPermissionsQuery);
+    const [[result], dbType] = await Promise.all([
+      dbQuery(parentPermissionsQuery),
+      getDBType(),
+    ]);
     for (const row of result) {
-      parentPermissions[row.user.toString()] = row.permissions;
+      parentPermissions[row.user.toString()] =
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions);
     }
     return parentPermissions;
   })();
diff --git a/keyserver/src/fetchers/upload-fetchers.js b/keyserver/src/fetchers/upload-fetchers.js
--- a/keyserver/src/fetchers/upload-fetchers.js
+++ b/keyserver/src/fetchers/upload-fetchers.js
@@ -4,6 +4,7 @@
 import { ServerError } from 'lib/utils/errors';
 
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { Viewer } from '../session/viewer';
 import { getAndAssertCommAppURLFacts } from '../utils/urls';
 
@@ -80,8 +81,12 @@
 }
 
 async function mediaFromRow(row: Object): Promise<Media> {
+  const dbType = await getDBType();
+  const uploadExtra =
+    dbType === 'mysql5.7' ? row.uploadExtra : JSON.parse(row.uploadExtra);
+  const { width, height, loop } = uploadExtra;
+
   const { uploadType: type, uploadSecret: secret } = row;
-  const { width, height, loop } = row.uploadExtra;
   const id = row.uploadID.toString();
   const dimensions = { width, height };
   const uri = getUploadURL(id, secret);
diff --git a/keyserver/src/push/rescind.js b/keyserver/src/push/rescind.js
--- a/keyserver/src/push/rescind.js
+++ b/keyserver/src/push/rescind.js
@@ -9,6 +9,7 @@
 
 import createIDs from '../creators/id-creator';
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { SQLStatementType } from '../database/types';
 import { getAPNsNotificationTopic } from './providers';
 import { apnPush, fcmPush } from './utils';
@@ -36,16 +37,19 @@
   `);
   fetchQuery.append(notifCondition);
   fetchQuery.append(SQL` GROUP BY n.id, m.user`);
-  const [fetchResult] = await dbQuery(fetchQuery);
+  const [[fetchResult], dbType] = await Promise.all([
+    dbQuery(fetchQuery),
+    getDBType(),
+  ]);
 
   const deliveryPromises = {};
   const notifInfo = {};
   const rescindedIDs = [];
   const receivingDeviceTokens = [];
   for (const row of fetchResult) {
-    const deliveries = Array.isArray(row.delivery)
-      ? row.delivery
-      : [row.delivery];
+    const rawDelivery =
+      dbType === 'mysql5.7' ? row.delivery : JSON.parse(row.delivery);
+    const deliveries = Array.isArray(rawDelivery) ? rawDelivery : [rawDelivery];
     const id = row.id.toString();
     const threadID = row.thread.toString();
     notifInfo[id] = {
diff --git a/keyserver/src/push/send.js b/keyserver/src/push/send.js
--- a/keyserver/src/push/send.js
+++ b/keyserver/src/push/send.js
@@ -33,6 +33,7 @@
 import createIDs from '../creators/id-creator';
 import { createUpdates } from '../creators/update-creator';
 import { dbQuery, SQL, mergeOrConditions } from '../database/database';
+import { getDBType } from '../database/db-config';
 import type { CollapsableNotifInfo } from '../fetchers/message-fetchers';
 import { fetchCollapsableNotifs } from '../fetchers/message-fetchers';
 import { fetchServerThreadInfos } from '../fetchers/thread-fetchers';
@@ -752,17 +753,26 @@
       SQL`AND device_token NOT IN (${excludeDeviceTokens}) `,
     );
   }
-  const [unreadCounts, [deviceTokenResult], [dbID]] = await Promise.all([
+  const [
+    unreadCounts,
+    [deviceTokenResult],
+    [dbID],
+    dbType,
+  ] = await Promise.all([
     getUnreadCounts([userID]),
     dbQuery(deviceTokenQuery),
     createIDs('notifications', 1),
+    getDBType(),
   ]);
   const unreadCount = unreadCounts[userID];
 
   const devices = deviceTokenResult.map(row => ({
     deviceType: row.platform,
     deviceToken: row.device_token,
-    codeVersion: row.versions?.codeVersion,
+    codeVersion:
+      dbType === 'mysql5.7'
+        ? row.versions?.codeVersion
+        : JSON.parse(row.versions)?.codeVersion,
   }));
   const byDeviceType = getDevicesByDeviceType(devices);
 
diff --git a/keyserver/src/session/cookies.js b/keyserver/src/session/cookies.js
--- a/keyserver/src/session/cookies.js
+++ b/keyserver/src/session/cookies.js
@@ -27,6 +27,7 @@
 import createIDs from '../creators/id-creator';
 import { createSession } from '../creators/session-creator';
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import { deleteCookie } from '../deleters/cookie-deleters';
 import { handleAsyncPromise } from '../responders/handlers';
 import { clearDeviceToken } from '../updaters/device-token-updaters';
@@ -89,8 +90,9 @@
     FROM cookies
     WHERE id = ${cookieID} AND user IS NOT NULL
   `;
-  const [[result], allSessionInfo] = await Promise.all([
+  const [[result], dbType, allSessionInfo] = await Promise.all([
     dbQuery(query),
+    getDBType(),
     fetchSessionInfo(sessionParameterInfo, cookieID),
   ]);
   if (result.length === 0) {
@@ -111,10 +113,14 @@
   const cookieRow = result[0];
   let platformDetails = null;
   if (cookieRow.versions) {
+    const versions =
+      dbType === 'mysql5.7'
+        ? cookieRow.versions
+        : JSON.parse(cookieRow.versions);
     platformDetails = {
       platform: cookieRow.platform,
-      codeVersion: cookieRow.versions.codeVersion,
-      stateVersion: cookieRow.versions.stateVersion,
+      codeVersion: versions.codeVersion,
+      stateVersion: versions.stateVersion,
     };
   } else {
     platformDetails = { platform: cookieRow.platform };
@@ -176,8 +182,9 @@
     FROM cookies
     WHERE id = ${cookieID} AND user IS NULL
   `;
-  const [[result], allSessionInfo] = await Promise.all([
+  const [[result], dbType, allSessionInfo] = await Promise.all([
     dbQuery(query),
+    getDBType(),
     fetchSessionInfo(sessionParameterInfo, cookieID),
   ]);
   if (result.length === 0) {
@@ -198,10 +205,14 @@
   const cookieRow = result[0];
   let platformDetails = null;
   if (cookieRow.platform && cookieRow.versions) {
+    const versions =
+      dbType === 'mysql5.7'
+        ? cookieRow.versions
+        : JSON.parse(cookieRow.versions);
     platformDetails = {
       platform: cookieRow.platform,
-      codeVersion: cookieRow.versions.codeVersion,
-      stateVersion: cookieRow.versions.stateVersion,
+      codeVersion: versions.codeVersion,
+      stateVersion: versions.stateVersion,
     };
   } else if (cookieRow.platform) {
     platformDetails = { platform: cookieRow.platform };
@@ -261,7 +272,7 @@
     FROM sessions
     WHERE id = ${session} AND cookie = ${cookieID}
   `;
-  const [result] = await dbQuery(query);
+  const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
   if (result.length === 0) {
     return null;
   }
@@ -269,7 +280,8 @@
     sessionID,
     lastValidated: result[0].last_validated,
     lastUpdate: result[0].last_update,
-    calendarQuery: result[0].query,
+    calendarQuery:
+      dbType === 'mysql5.7' ? result[0].query : JSON.parse(result[0].query),
   };
 }
 
diff --git a/keyserver/src/updaters/thread-permission-updaters.js b/keyserver/src/updaters/thread-permission-updaters.js
--- a/keyserver/src/updaters/thread-permission-updaters.js
+++ b/keyserver/src/updaters/thread-permission-updaters.js
@@ -30,6 +30,7 @@
   type UpdatesForCurrentSession,
 } from '../creators/update-creator';
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import {
   fetchServerThreadInfos,
   rawThreadInfosFromServerThreadInfos,
@@ -116,11 +117,13 @@
     WHERE t.id = ${threadID} AND cm.user IN (${userIDs})
   `;
   const [
+    dbType,
     [membershipResults],
     [parentMembershipResults],
     containingMembershipResults,
     roleThreadResult,
   ] = await Promise.all([
+    getDBType(),
     dbQuery(membershipQuery),
     dbQuery(parentMembershipQuery),
     (async () => {
@@ -148,8 +151,12 @@
     const userID = row.user.toString();
     existingMembershipInfo.set(userID, {
       oldRole: row.role.toString(),
-      oldPermissions: row.permissions,
-      oldPermissionsForChildren: row.permissions_for_children,
+      oldPermissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
+      oldPermissionsForChildren:
+        dbType === 'mysql5.7'
+          ? row.permissions_for_children
+          : JSON.parse(row.permissions_for_children),
     });
   }
 
@@ -160,7 +167,10 @@
       continue;
     }
     ancestorMembershipInfo.set(userID, {
-      permissionsFromParent: row.permissions_from_parent,
+      permissionsFromParent:
+        dbType === 'mysql5.7'
+          ? row.permissions_from_parent
+          : JSON.parse(row.permissions_from_parent),
     });
   }
   for (const row of containingMembershipResults) {
@@ -352,7 +362,7 @@
       INNER JOIN roles r ON r.thread = t.id AND r.id = ${role}
       WHERE t.id = ${threadID}
     `;
-    const [result] = await dbQuery(query);
+    const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
     if (result.length === 0) {
       throw new ServerError('internal_error');
     }
@@ -365,7 +375,8 @@
         ? row.parent_thread_id.toString()
         : null,
       hasContainingThreadID: row.containing_thread_id !== null,
-      rolePermissions: row.permissions,
+      rolePermissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
     };
   } else {
     const query = SQL`
@@ -375,7 +386,7 @@
       INNER JOIN roles r ON r.thread = t.id AND r.id = t.default_role
       WHERE t.id = ${threadID}
     `;
-    const [result] = await dbQuery(query);
+    const [[result], dbType] = await Promise.all([dbQuery(query), getDBType()]);
     if (result.length === 0) {
       throw new ServerError('internal_error');
     }
@@ -388,7 +399,8 @@
         ? row.parent_thread_id.toString()
         : null,
       hasContainingThreadID: row.containing_thread_id !== null,
-      rolePermissions: row.permissions,
+      rolePermissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
     };
   }
 }
@@ -573,27 +585,30 @@
   const threadIDs = ancestors.map(ancestor => ancestor.threadID);
 
   const rows = [];
-  while (threadIDs.length > 0) {
-    const batch = threadIDs.splice(0, fetchDescendantsBatchSize);
-    const query = SQL`
-      SELECT t.id, m.user, t.type, t.depth, t.parent_thread_id,
-        t.containing_thread_id, r.permissions AS role_permissions, m.permissions,
-        m.permissions_for_children, m.role,
-        pm.permissions_for_children AS permissions_from_parent,
-        cm.role AS containing_role
-      FROM threads t
-      INNER JOIN memberships m ON m.thread = t.id
-      LEFT JOIN memberships pm
-        ON pm.thread = t.parent_thread_id AND pm.user = m.user
-      LEFT JOIN memberships cm
-        ON cm.thread = t.containing_thread_id AND cm.user = m.user
-      LEFT JOIN roles r ON r.id = m.role
-      WHERE t.parent_thread_id IN (${batch})
-        OR t.containing_thread_id IN (${batch})
-    `;
-    const [results] = await dbQuery(query);
-    pushAll(rows, results);
-  }
+  const queriesPromise = (async () => {
+    while (threadIDs.length > 0) {
+      const batch = threadIDs.splice(0, fetchDescendantsBatchSize);
+      const query = SQL`
+        SELECT t.id, m.user, t.type, t.depth, t.parent_thread_id,
+          t.containing_thread_id, r.permissions AS role_permissions, m.permissions,
+          m.permissions_for_children, m.role,
+          pm.permissions_for_children AS permissions_from_parent,
+          cm.role AS containing_role
+        FROM threads t
+        INNER JOIN memberships m ON m.thread = t.id
+        LEFT JOIN memberships pm
+          ON pm.thread = t.parent_thread_id AND pm.user = m.user
+        LEFT JOIN memberships cm
+          ON cm.thread = t.containing_thread_id AND cm.user = m.user
+        LEFT JOIN roles r ON r.id = m.role
+        WHERE t.parent_thread_id IN (${batch})
+          OR t.containing_thread_id IN (${batch})
+      `;
+      const [results] = await dbQuery(query);
+      pushAll(rows, results);
+    }
+  })();
+  const [dbType] = await Promise.all([getDBType(), queriesPromise]);
 
   const descendantThreadInfos: Map<string, DescendantInfo> = new Map();
   for (const row of rows) {
@@ -616,10 +631,20 @@
     const userID = row.user.toString();
     descendantThreadInfo.users.set(userID, {
       curRole: row.role.toString(),
-      curRolePermissions: row.role_permissions,
-      curPermissions: row.permissions,
-      curPermissionsForChildren: row.permissions_for_children,
-      curPermissionsFromParent: row.permissions_from_parent,
+      curRolePermissions:
+        dbType === 'mysql5.7'
+          ? row.role_permissions
+          : JSON.parse(row.role_permissions),
+      curPermissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
+      curPermissionsForChildren:
+        dbType === 'mysql5.7'
+          ? row.permissions_for_children
+          : JSON.parse(row.permissions_for_children),
+      curPermissionsFromParent:
+        dbType === 'mysql5.7'
+          ? row.permissions_from_parent
+          : JSON.parse(row.permissions_from_parent),
       curMemberOfContainingThread: row.containing_role > 0,
     });
   }
@@ -724,10 +749,12 @@
     WHERE t.id = ${threadID}
   `;
   const [
+    dbType,
     [threadResults],
     [membershipResults],
     [parentMembershipResults],
   ] = await Promise.all([
+    getDBType(),
     dbQuery(threadQuery),
     dbQuery(membershipQuery),
     dbQuery(parentMembershipQuery),
@@ -750,9 +777,16 @@
     const userID = row.user.toString();
     membershipInfo.set(userID, {
       role: row.role.toString(),
-      permissions: row.permissions,
-      permissionsForChildren: row.permissions_for_children,
-      rolePermissions: row.role_permissions,
+      permissions:
+        dbType === 'mysql5.7' ? row.permissions : JSON.parse(row.permissions),
+      permissionsForChildren:
+        dbType === 'mysql5.7'
+          ? row.permissions_for_children
+          : JSON.parse(row.permissions_for_children),
+      rolePermissions:
+        dbType === 'mysql5.7'
+          ? row.role_permissions
+          : JSON.parse(row.role_permissions),
       memberOfContainingThread: !!(
         row.containing_role && row.containing_role > 0
       ),
@@ -760,12 +794,16 @@
   }
   for (const row of parentMembershipResults) {
     const userID = row.user.toString();
+    const permissionsFromParent =
+      dbType === 'mysql5.7'
+        ? row.permissions_from_parent
+        : JSON.parse(row.permissions_from_parent);
     const membership = membershipInfo.get(userID);
     if (membership) {
-      membership.permissionsFromParent = row.permissions_from_parent;
+      membership.permissionsFromParent = permissionsFromParent;
     } else {
       membershipInfo.set(userID, {
-        permissionsFromParent: row.permissions_from_parent,
+        permissionsFromParent: permissionsFromParent,
       });
     }
   }
diff --git a/keyserver/src/updaters/thread-updaters.js b/keyserver/src/updaters/thread-updaters.js
--- a/keyserver/src/updaters/thread-updaters.js
+++ b/keyserver/src/updaters/thread-updaters.js
@@ -31,6 +31,7 @@
 import { getRolePermissionBlobs } from '../creators/role-creator';
 import { createUpdates } from '../creators/update-creator';
 import { dbQuery, SQL } from '../database/database';
+import { getDBType } from '../database/db-config';
 import { fetchEntryInfos } from '../fetchers/entry-fetchers';
 import { fetchMessageInfos } from '../fetchers/message-fetchers';
 import {
@@ -531,9 +532,15 @@
           LEFT JOIN roles r ON r.id = t.default_role
           WHERE t.id = ${request.threadID}
         `;
-        const [result] = await dbQuery(rolePermissionsQuery);
+        const [[result], dbType] = await Promise.all([
+          dbQuery(rolePermissionsQuery),
+          getDBType(),
+        ]);
         if (result.length > 0) {
-          rolePermissions = result[0].permissions;
+          rolePermissions =
+            dbType === 'mysql5.7'
+              ? result[0].permissions
+              : JSON.parse(result[0].permissions);
         }
       }
       if (!rolePermissions) {