Signature modes

CodeTwo Email Signatures 365 can operate in one of three signature modes: cloud (aka server-side), Outlook (aka client-side) and combo. You first select a signature mode when you add your Microsoft 365 tenant to CodeTwo, but you can change the signature mode later on.

The video below explains in a nutshell how each signature mode works. For more detailed information, continue reading the article.

Quick comparison between signature modes

Cloud (server-side) mode

In the cloud mode, CodeTwo signatures are added to emails sent from any email app and device. When registering a tenant to CodeTwo Email Signatures 365 for the first time, we will create Exchange Online connectors and a transport rule that will reroute emails (both internal and external) sent from your Microsoft 365 tenant through the CodeTwo cloud service for processing (this is where the signature is added). The entire mail flow is shown in Fig. 1.

Fig. 1. Mail flow in Microsoft 365 with CodeTwo Email Signatures 365 working in the cloud (server-side) mode.

During tenant registration, you also:

• select the Azure region where your signatures will be added and your settings stored (e.g. the same region where your Microsoft 365 tenant resides, for compliance reasons),
• specify a scope of senders whose emails are rerouted through the CodeTwo service (to get cloud signatures).

See our video tutorial or check these instructions to learn how to register your tenant to CodeTwo and configure our service to work in the cloud mode. 

CodeTwo cloud signatures are added to emails sent by or to specific users, based on configured cloud (server-side) signature rules (see configuration instructions). Users can preview CodeTwo cloud signature that will be added to an email by using the dedicated Outlook Web Add-in but they cannot make any changes to that signature. Signatures can also be viewed in the Sent Items folder after deploying the Sent Items Update feature. You can create multiple CodeTwo cloud signatures for a single end user.

In addition, when CodeTwo Email Signatures 365 works in the cloud mode, you can also enable Autoresponder to create and manage automatic replies for all users in your tenant. Learn more about this free feature

Outlook (client-side) mode

If CodeTwo Email Signatures 365 works in the Outlook mode, signatures are added directly to email body as end users type an email in Outlook. In this mode, emails are not routed through the CodeTwo cloud service, so connectors & transport rule configuration is not required. Instead, signatures are added by our Outlook Web Add-in (as shown in Fig. 2.).

Fig. 2. Mail flow in Microsoft 365 with CodeTwo Email Signatures 365 working in the Outlook (client-side) mode.

To make CodeTwo Outlook signatures available for your end users, you need to:

• create an Outlook (client-side) signature rule,
• deploy CodeTwo Outlook Web Add-in (deployment is completely automated & centralized; no end-user installation required).

You can create multiple CodeTwo Outlook signatures for a single end user, but you can set only one default signature for new messages and one default for replies and forwards. As opposed to CodeTwo cloud signatures, users can freely choose and edit their signatures in Outlook before sending an email.

When CodeTwo Email Signatures 365 works in the Outlook mode, you cannot use the Autoresponder feature. Autoresponder requires the configuration of Exchange Online connectors. Learn more

Combo mode

Combo mode combines the functionalities of the cloud (server-side) and the Outlook (client-side) signature mode, offering additional benefits. In combo mode, you can use two types of email signatures:

• Outlook signatures, added directly to the email body by a CodeTwo Web Add-in as end users compose their emails in any Outlook app (desktop, mobile & OWA).
• cloud signatures, added in the cloud, after an email is sent, if end users use other email apps. 

This mode is well-suited for scenarios where you want to provide users with more control over their email signatures, allowing them to manually select their signature from the Web Add-in's pane (available in Outlook for Windows, Mac & OWA). It also ensures that your organization's signature is added when sending emails from apps other than Outlook.

If you select this mode, you need to:

• create Exchange Online connectors and a transport rule that will reroute emails through CodeTwo and select users who will get cloud signatures (this is done during tenant registration),
• deploy CodeTwo Outlook Web Add-in to uses who will get Outlook signatures,
• create both cloud (server-side) and Outlook (client-side) signature rules.

Additionally, when using combo mode, you can allow your users to switch between their cloud and Outlook signatures on their own, directly from the Web Add-in's pane. For more information about this feature, see the video below or read this article.

How does mail flow work in combo mode?

In combo mode (Fig. 3.), some emails are routed through CodeTwo:

• Emails do not go through the CodeTwo service if they are sent from Outlook (desktop, OWA & mobile devices) and they already have a signature added by the CodeTwo Web Add-in. If an Outlook signature is added to the email and then manually removed from it by a user, the email still won't be routed through CodeTwo. 
• Emails go through the CodeTwo service (located in the Azure region selected during tenant registration):
  • if they are sent from Outlook but the email sender does not have the CodeTwo Web Add-in or is not included in Outlook (client-side) signature rules;
  • if they are sent from an old version of Outlook on iOS & Android (4.2425.0 and earlier) – old Outlooks have limited Web Add-in support and our service is required to avoid double signatures;
  • if they are sent from email apps other than Outlook.

Fig. 3. Mail flow in Microsoft 365 with CodeTwo Email Signatures 365 working in the combo mode.

How to change signature mode

You can change the signature mode at any time in CodeTwo Admin Panel. But before you proceed, read the following section to ensure your email signatures and automatic replies continue working without interruption.

Before you change signature mode

If you're changing the mode from cloud (server-side) to Outlook (client-side) or vice versa, your organization's signatures might be interrupted during the change. To minimize the impact, follow these steps:

1. Create email signature rules for the new signature mode in advance. You can easily convert your existing signature rules from one type to another (as explained in this article) or set up new rules from scratch (see guidelines).
2. If you're switching from cloud mode to Outlook mode, then:
   • Before the change, deploy our Outlook Web Add-in to users who previously used the cloud (server-side) signatures. It's very easy - see our video tutorial or these instructions. Note that it usually takes up to 6 hours for the add-in to appear in Outlook, but the deployment can take up to 72 hours depending on your organization's size. 
   • Consider changing the signature mode to combo. Even after the add-in deployment, it can take up to 4 hours for the change in signature mode to propagate and for the add-in to start adding signatures. Switching to combo mode ensures that your current (cloud) signatures continue to work. And once the add-in starts inserting signatures to emails sent from Outlook, these emails will no longer get cloud signatures (you won't end up with duplicate signatures). You can then continue using combo mode (see the benefits) or disable cloud signatures and make a final switch to Outlook mode.
   • Changing the signature mode to Outlook will disable the Autoresponder feature. To keep this functionality, consider switching to combo mode instead.

Change signature mode in CodeTwo Admin Panel

To change your current signature mode, sign in to CodeTwo Admin Panel. On the Tenants page, select your Microsoft 365 tenant to open its settings. Next, go to Signature mode, select the signature mode and apply your change (Fig. 4.).

Fig. 4. Changing the signature mode in CodeTwo Admin Panel.

Additional configuration is required when changing the signature mode from or to Outlook (client-side). A wizard will open that will help you:

• configure Exchange Online connectors and transport rule that reroute your tenant's email through CodeTwo; or
• remove the existing CodeTwo connectors and transport rule. Learn more about configuring Exchange Online connectors

Check the following section to learn what steps you need to take to ensure your end users will continue to get CodeTwo signatures.

Next steps after changing signature mode

Depending on what signature mode you used and what signature mode you switch to, some additional steps might be needed:

• Cloud (server-side) to Outlook (client-side)
• Cloud (server-side) to combo
• Outlook (client-side) to cloud (server-side)
• Outlook (client-side) to combo 
• Combo to cloud (server-side)
• Combo to Outlook (client-side)

Next steps: change from cloud (server-side) to Outlook (client-side) mode

We recommend completing these steps before changing the signature mode from cloud to Outlook. This is crucial because cloud signatures will no longer work after the change, resulting in your end users not receiving any signatures. If you haven't done so yet, complete these steps now:

1. Convert your existing cloud signatures to Outlook signatures (learn more) or set up CodeTwo Outlook signatures from scratch (see instructions) for the users who previously used CodeTwo cloud signatures.
2. Deploy CodeTwo Outlook Web Add-in to these users (see instructions).
3. When the deployment is complete, your end users will get their signatures when typing an email in Outlook (desktop, mobile & web/OWA).

Next steps: change from cloud (server-side) to combo mode

CodeTwo signatures continue to be added in the cloud to emails sent from any device or email app. If you want your end users to get their signatures directly to emails typed in Outlook (desktop, mobile & web/OWA), you need to:

1. Convert your existing cloud signatures to Outlook signatures (learn more) or set up CodeTwo Outlook signatures for your end users from scratch (see instructions). 
2. Deploy CodeTwo Outlook Web Add-in to users who will get CodeTwo Outlook signatures (see instructions).

Next steps: change from Outlook (client-side) to cloud (server-side) mode

We recommend creating cloud signatures before changing the signature mode from Outlook to cloud. This is crucial because Outlook signatures will no longer work after the change, resulting in your end users not receiving any signatures. If you haven't done so yet, convert your existing Outlook signatures to cloud signatures (learn more) or configure CodeTwo cloud signatures for your end users from scratch (see instructions). 

Your end users can continue to use the Outlook Web Add-in to preview CodeTwo cloud signatures. 

If you no longer need the add-in, you can remove it for all end users by following these instructions.

Next steps: change from Outlook (client-side) to combo mode

CodeTwo signatures continue to be added by our Outlook Web Add-in to emails in Outlook (desktop, mobile & web/OWA). If you want your end users to also get their signatures in the cloud when sending an email from any device or different email apps, you need to convert your existing Outlook signatures to cloud signatures (learn more) or configure CodeTwo cloud signatures for your end users from scratch (see instructions). 

Next steps: change from combo to cloud (server-side) mode

CodeTwo signatures continue to be added in the cloud to emails sent from any device or email app. Make sure to convert your existing Outlook signatures to cloud signatures (learn more) or configure CodeTwo cloud signatures from scratch for end users who previously used CodeTwo Outlook signatures only (see instructions). 

Your end users can continue to use our Outlook Web Add-in to preview CodeTwo cloud signatures.

If you no longer need the add-in, you can remove it for all users by following these instructions.

Next steps: change from combo to Outlook (client-side) mode

CodeTwo signatures continue to be added by our Outlook Web Add-in to emails in Outlook (desktop, mobile & web/OWA). Make sure to convert your existing cloud signatures to Outlook signatures (learn more) or configure CodeTwo Outlook signatures from scratch for end users who previously used CodeTwo cloud signatures only (see instructions).