Reading an iMessage without the option to mark it as unread can sometimes lead to forgotten replies, especially if you're unable to respond immediately. Unfortunately, iOS doesn't currently offer a native feature to mark messages as unread. However, there are effective workarounds to help you remember to get back to those important conversations.

Ask Siri to set a reminder

One of the simplest ways to ensure you don't forget to reply is by having Siri remind you. Setting up a reminder via Siri is quick and doesn't interrupt your workflow.

Step 1: While viewing the message thread in the Messages app, activate Siri by saying Hey Siri or by pressing the Home button.

Step 2: Instruct Siri by saying, "Remind me about this in one hour" or specify a different time frame that suits your schedule.

This action will create a reminder linked directly to the message. When the time comes, you'll receive a notification prompting you to respond.

Forward the message to yourself

If you prefer a visual reminder within your Messages app, forwarding the message to yourself can be useful. This way, the message appears as unread in your conversations list.

Step 1: In the conversation, locate the specific message you want to be reminded about. Press and hold on that message until options appear.

Step 2: Tap on 'More...' from the menu that appears below the message.

Step 3: Select the forward arrow icon located at the bottom-right corner of the screen.

Step 4: In the 'To:' field, enter your own contact details and send the message to yourself.

This forwarded message will appear as a new, unread conversation in your Messages app, serving as a prompt to address the original message later.

Until Apple introduces an option to mark iMessages as unread, these methods can help ensure you don't overlook important messages that require your attention.