STEM version 7.5a release

31 October 2016

Available to all clients with a current maintenance contract

STEM 7.5 is finally ready! Or, more precisely, STEM 7.5 has been available to a small group of early adopters since July 2016, and now a STEM 7.5a point release is available as a recommended update for all users. So what does that mean for you?

  1. This system has been tested across a wide variety of customer models on existing patches to the original STEM 7.5 release which have been in regular use since early August. It offers the best functionality and performance available today, including zoom in the Editor and a completely revamped results-selection interface. If your company has a current maintenance contract, then you should consider upgrading from STEM 7.4 at the earliest opportunity if you have not already done so, or from any earlier STEM 7.5 build.
  2. We won’t usually fix bugs in older systems unless you have a current maintenance agreement and a compelling business reason to use the older version in preference to upgrading to the latest system. So you can also expect the best support experience if you migrate to using what we now regard as the current platform.

Evolution from the original STEM 7.5 version

Just before the summer break in the northern hemisphere was never going to be a great time to issue a major software release. Many of our clients would soon be on holiday, and so would some of our key staff. However, our internal testing milestones were complete and a few specific clients were keen to get their hands on the long-awaited features described in our earlier newsletter article. Moreover an opportunity arose to supervise the first installations on a series of consulting projects in late July and August.

Therefore we quietly released the first official STEM 7.5 system in mid-July, and have since issued a series of patches to address urgent issues which were not detected by our own testing. In fact no further patching has been required since mid-August; the main differences you will see in STEM version 7.5a relate to a number of minor refinements we have made since the original version 7.5 was released:

  • to complete our original target functionality
  • to address a few unforeseen issues with the new design, or
  • to respond to feedback received during the recent STEM User Group Meeting.

A detailed list of changes is included at the end of this article.

Installation instructions and guidance on compatibility

STEM 7.5a is available to new and existing clients with a current maintenance contract. Please download the new system when convenient from the Installation files area of our website, or directly from the download panel opposite, and contact if you have any difficulty accessing it.

STEM 7.5a is fully compatible with models created in version 7.4 or the original 7.5, but models saved with STEM 7.5a (or 7.5) cannot be read back into STEM 7.4 or earlier versions without manual input from support.

This one-way compatibility is common in software where older systems will typically fail to recognise attributes introduced by a newer system. Traditionally it was not too hard to ‘reverse’ a STEM model version, where the only real loss was those newer attributes which would have no meaning for the older version. However, the STEM 7.5 upgrade will touch all model elements (with a new GUID property for more robust identification of results) and potentially alter the settings of one or two attributes whose interpretation has been amended in the new version. Therefore such a roll-back eventuality should be avoided in all but the most compelling circumstances.

You may wish to keep working with STEM 7.4 for an initial period while you try out the new version and satisfy yourself that any mission-critical models behave ‘as normal’. With this in mind, the installers are designed so that it is not necessary to uninstall STEM 7.4 before installing STEM 7.5a. Once the newer version is installed, double-clicking a model file will then always start the newer version; so you will need to use drag-and-drop or Open from the File menu to load a model into the older version when required.

Of course, if you do choose to retain a STEM 7.4 installation, then it is essential to install STEM 7.5a in a different folder. However, as you will see, the new version installs into C:\Program Files (x86)\Implied Logic\STEM 7.5a by default, so this is unlikely to be a problem in practice.

Note: If you have been working with the original STEM 7.5, then the same logic applies. You can install and try out STEM 7.5a before removing the original version if you prefer.

What’s new in STEM 7.5a

Anyone who has been using the original STEM 7.5 may note the following changes:


  1. An obscure and apparently random crash in the Editor, sometimes but not always mentioning an ‘invalid type’, has been diagnosed and fixed.
  2. Find and Replace suggests common text, if possible, cf. Copy and Replace, and the algorithm for identifying this common text has been slightly refined.
  3. The selection of icons is maintained after Find and Replace.
  4. Copy and Replace now works properly when copying to a different model.
  5. Prompt only once for the Basis when creating requirements (for a single resource) with drag-and-drop from a multiple selection of services or transformations.
  6. Arrange Visible now respects the new Requirement 2 and Input 2 link types.
  7. View names in the Editor are no longer limited to 31 characters.
  8. Less ‘flicker’ when opening a model with lots of Editor views.
  9. Facility to activate the File menu from any dialog by pressing <Alt+F> re-instated with the latest Windows 10 update.
  10. <Ctrl+Shift+T> still creates new elements, even after cancelling a Find and Replace.


  1. Generated files are still retained even if a model has only been opened recently (but not saved or run).
  2. A more recent .dtm file in the Generated folder is now discarded if you manually replace a .dtl file with an older version.
  3. A recovered, autosaved model now gets the correct relative path for a custom icon file.
  4. Check for expiring soft-licence deferred until after loading command-line models.
  5. A run-time model created with D-STEM now only prompts once to accept end-user licence terms when parallel-processing multiple scenarios.
  6. Bug fixed regarding eSTEM processing of a model name including the ‘.’ character.
  7. LTE example model no longer generates a replication error with STEM 7.5a.
  8. Cable example model included with the 7.5a installer.


  1. It is now optional whether collections should appear First, Last, Inline or By Type in the Elements, Variants and Cost Breakdown tabs when drawing a graph.
  2. Tornado charts working again when parameters are affected by template replication.
  3. The Cost Breakdown tab for results selection in a model that uses template replication now works as originally intended, namely that just resources are listed rather than resource/variant pairs when Linear Selection is not active.
  4. The Cost Breakdown tab also now correctly handles services as RHS elements when an intermediate service specifies Value Chain = Cross Charge.
  5. Some bug fixes for graphs using the new Slice functionality across either scenarios, after a dimension is added or removed, or template variants.
  6. The automatic stacked (column) format of a cost or revenue graph (aggregate result) for several elements in the same scenario no longer incorrectly persists if Change Selections is used to show a demand result (instantaneous, line format) instead.
  7. Copy Picture functionality restored for results graphs and tables (including titles).
  8. The Current View and All Views options now work properly when changing fonts on results graphs.
  9. Scenario results still up-to-date after modifying only the working model.

STEM 7.5a installer

Registered licensees with a current maintenance contract can download the appropriate C-STEM, D-STEM or eSTEM installer.

Download now: C-STEM 7.5D-STEM 7.5eSTEM 7.5

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