Whilst I'm posting this in August (wow, August already), the July update of ZPE, known as ZPE 1.4.3, is by far the biggest change to ZPE since 1.4.0. Although a lot of the changes described here were marked as being under version 1.4.2, they were only available as part of the experimental mode during that version.
This update is a huge update to the RMM parser and replaces it (largely) with the LAMP parser - a logic and mathematical parser.
This update makes it more efficient as both logic and maths are processed together. ZPE 1.4.3 also reduces the size of compiled programs and improves the efficiency of the code when interpreted. Another major change that was brought in was the unification of logical symbols - the word "AND" is the exact same now as "&&". This will again improve the efficiency of the interpreter and reduces the number of checks done there. Logical and mathematical expressions are now also assessed (not evaluated) as to being a logical or mathematical expression at compile time thus reducing the time spent assessing at runtime.
1.4.3.10 fixes structures as promised and unifies them with the object type with a bit more flexibility. Global variables and constants can now be assigned to be public, private and friendly within scripts, giving more power over their scope.
1.4.3 also drops the XOR from the logic parsing, but adds the xor function to the built-in functionalities. 1.4.3.10 also made a change for associative arrays since they no longer use the = sign to represent an association but the => symbol. I had many people saying they liked this in PHP when I did my feedback request in June and I had been planning to implement this since version 1.3.4 but it was still in the backburner. At last, I can finally say this is done (whilst this will lead to larger programs since there is one extra character, compiled programs will still be the same in size).
I deem this to be the best and most complete version of ZPE: 1.4.3 officially brings an end to my monthly update system (which has largely been kept to, but has occasionally fallen behind).
The next version of ZPE aims to bring in enumeration, although it is yet to be decided whether or not this is fully necessary.