We never had any issues from users updating to Mojave whilst still using Jaksta V2.5.5.
If you want to check the Kind (32-bit or 64-bit) of your current version you can check it by following the instructions under the 'Find 32-bit apps on your Mac through System Report' section on this page - https://www.macworld.com/article/3393161/how-to-check-if-mac-software-is-32-or-64-bit.html
My suggestion would be to do the Mac OS update and then see if there is a problem. If there is, we have a beta we can give you that should be compatible.
Please let me know how go.
I have Jaksta 2.2.5 on my iMac, OS 10.13.6. I am going to upgrade to Mojave and I am told that my current Jaksta 2.2.5 is NOT 64 bits. Please advise. Thanks.