Thank you for contacting us, and I'm sorry for the issue you are experiencing. I'm not sure what could be happening here. I just tested the migration of data from mSecure 4.5 to mSecure 5 with both attachments and customer icons, and everything worked as it was supposed to. After the migration, all of the attachments and custom icons are displayed in the app, and when I tap on the attachments, the larger image is displayed.
The only thing I can think of to try is to have you reset your mSecure 5 account, so you can try to migrate your data again. The other option would be to try to restore from a recent email backup you may have access to. Do you have an email backup you can restore from? If not, do you still have mSecure 4 installed on your phone, and do you want to try resetting the account to migrate the data again?
I'm sorry for the issue you are experiencing here with the photo attachments. Every now and again, we run into a customer experiencing this, but we have not been able to figure out what's causing it to happen. When upgrading from v4 to v5, all of the photo attachments are available locally, so there shouldn't be any problems getting them imported into the new app. Unfortunately, reinstalling and selecting iCloud syncing won't help the situation, because v5 places it's data synced to icloud in a different folder than v4 did. The best solution would be to try restoring from a backup file, but I'm not sure that's possible here. Do you know if you a recent email backup that would have been made in mSecure 4?
If you don't have a backup file, I have something I want to try, but it's not something I have done before. It's possible that all that's missing in the new sync location is the encrypted photos, so we may be able to fix this by copying the old "attachments" folder to the new location. We'll try that if you don't have a backup to restore from.
I wasn't thinking about phone and icloud available space, that could be what's causing this issue. This happens so infrequently, that's it's hard to keep a good trail of info as to what might be causing it, but that infrequency might actually be the clue leading to it being about a lack of space on either the device, iCloud Drive or both. Even though their can be what seems to be more than enough space to store data, when it gets low enough, all sorts of problems can take place due to the need for memory swapping. At this time, I'm not sure this is the cause, but it seems reasonable.
I just realized that my idea from before won't work as I had thought. In mSecure 5, there is a very secure key called an "Account Key" that is actually responsible for encrypting your data. Even though you might be using the same password in mSecure 5 as you were in v4, the Account Key in v5 won't match the password you were using in v4, so even if mSecure wanted to bring in the photos from iCloud, they wouldn't be able to be decrypted.
However, I have a different idea. Now that you have your data in mSecure 5, without the attachments of course, we can try to see if reinstalling mSecure 4 is possible. If it is, then we can try to sync in the data from your iCloud account. For some, reinstalling the older version does work, so this is worth a try. We never try this without the data already migrated to mSecure 5, because it will delete the v4 data stored locally on the device, and it's possible the remote sync password will not be known for syncing in the data from your iCloud account. With the state you're in now, I don't think trying this would hurt, because if you don't try it, the photos won't be available in mSecure 5 anyhow.
I hope that all makes sense, but if not, please let me know before proceed. I'll wait to hear back from you, and then I'll send instructions for reinstalling mSecure 4 if that's the route you want to take.
Thank you for the extra information here. First, feel free to create a new backup of your data in v5. That is a very good thing to do as we're contemplating troubleshooting the photos issue =) Should anything go wrong, you'll always be able to go back to that data state with a quick restore.
For iCloud syncing, things were done differently in mSecure 4 than in mSecure 5. The older app was using an older API for iCloud interoperability, and so the data wasn't exposed in a folder. It was an API used before iCloud Drive exposed the documents in your iCloud account like it does now. Unfortunately, it's not possible to get at that data and then move it around like you can now. However, you should still be able to sync the data in from iCloud if you were able to reinstall mSecure 4, which we'll get to if something else doesn't work for getting your photos back.
After you make your email backup in v5, I'm going to have you reset your mSecure 5 account and try the migration again from v4. We have had some success doing this, so it is worth a try to see if some glitch may have caused the photos to be missed the first time around. You can reset the account by first deleting mSecure 5, then follow the instructions here: https://support.msecure.com/en/support/solutions/articles/36000064228-account-reset
After you have reset your account, install mSecure 5 and go through the sign in process where you'll be asked to migrate again. Were you able to do the migration again, and did the photos come in this time?
I am having the same issue above as Steve, i.e. missing all attachments after migrating from V4 to V5 and looking at the black screen with X and shareable arrow at each top corners after clicking on the attachment icon.