by: C.C. Chen & Alan Knutson

1. Postage evidencing systems

The USPS defines postage meters that allow the printing of meter stamps and PC postage products to print online postage as “postage evidencing systems” (PES). Currently, there are two types of performance standards for PES: the old IBI (information based indicia) standard introduced in the late 1990s and the newer IMI (intelligent mail indicia) standard launched back in 2013.

2. PES postage

PES, relying on IBI or IMI standards, require a postal security device (PSD). The PSD is a piece of hardware (for stamp vending machines or postage meters) or software (for online postage: “virtual PSD”) that can print (meter) postage stamps that comply with USPS standards. The PSD serves as a postage counter and fashions a cryptographically secured digital signature, which in turn is printed in the form of an indicium onto a label or envelope (IBI or IMI postage). The indicium is printed by postage meters, stamp vending machines, and all forms of PC postage products. It consists of a machine readable 2D code (codes, e.g., the denomination, mail class, date, origin Zip Code, destination Zip Code, and a possible tracking number) and human-readable information.

3. 2D codes used on PES postage

So far, four major types of 2D codes were/are used for PES postage (Figure 1):

3.1 PDF417

This code (Figure 1a) was used on kiosk postage (1st generation automated postal centers from IBM/Neopost and NCR) and Stamps.com Internet meter postage affixed to “Prepaid Forever Priority Mail Flat Rate packaging” sold by the USPS. It was and is still used for both IBI- and IMI-based online meter postage (E-Stamp, Neopost, Stamps.com, Endicia, Stamps.com/Endicia, Pitney Bowes, EasyPost, and ChitChats).

3.2 Four-symbol Data Matrix code

This code (Figure 1b) was/is used both for IBI and IMI postage: kiosk postage (2nd, 3rd, & 4th generation automated postal centers, Neopostage, and IBM Schaumburg kiosk), Internet postage stamps (SnapStamps, NetStamps, Stamp Expressions™, pbSmartPostage, and SendPro), online meter postage (Stamps.com, Endicia, Stamps.com/Endicia and Pitney Bowes), and meter postage (Neopost, Hasler, Quadient, Pitney Bowes, and Francotyp-Postalia). Without a decoder, it is impossible to check whether a particular four-symbol Data Matrix code is of IBI or IMI format.

Figure 1
Figure 1. 2D codes found on IBI and IMI postage. (a) PDF417, (b) four-symbol Data Matrix code, (c) vertical two-symbol Data Matrix code, (d) horizontal two-symbol Data Matrix code,and (e) one-symbol Data Matrix code. The symbols and respective numbers of columns and rows are indicated for the Data Matrix codes.

3.3 Two-symbol Data Matrix code (IBI Lite)

Depending on the type of postage printed, this 2D code is printed either vertically (Figure 1c) or horizontally (Figure 1d). It is found mainly on IBI but very rarely on IMI postage: kiosk postage (Forever stamps from automated postal centers [IBI and IMI], mail & go postage, and IBM Schaumburg kiosk), all types of custom postage (e.g., PhotoStamps, Zazzle Custom Stamps, PictureItPostage and their affiliates’ stamps), Internet postage stamps (NetStamps, InstaPostage, DYMO postage, pbSmartPostage, and SendPro [IBI and IMI]), online meter postage (Stamps.com, Endicia, Stamps.com/Endicia), and meter postage (Neopost, Hasler, Quadient, PitneyBowes, Francotyp-Postalia, and Data Pac).

3.4 One-symbol Data Matrix code

This code (Figure 1e) has only been used on portrait-formatted NetStamps. The one-symbol Data Matrix is the only code that is IMI-incompatible.

4. Transition from IBI to IMI standard

The IMI standard is basically more secure (better fraud detection), accurate, and cost-effective. Respective indicia contain more detailed (postage and transaction) data than IBI and can be obtained in real-time (e.g., IMI-compatible postage meters need to be connected to manufacturers’ servers every 72h), which allows the USPS to optimize mail logistics and minimize costly operations such as refunds or validations of proper postage payments.

Thus, the USPS mandated the transition from IBI to IMI standard as outlined in a Federal Register Notice on 12/04/2020 (Federal Register / Vol. 85, No. 234 / Friday, December 4, 2020 / Rules and Regulations; 78234-78236).

The following three key dates are important:

On June 30, 2024, all IBI-compatible PES will be decertified. For example, it will be no longer possible to rent or lease IBI-compatible postage meters.

All decertified PES must be withdrawn from service by December 31, 2024.

IBI postage will only be valid or eligible for refunds until June 30, 2025. This will be an important date for PES clients or collectors (to use up or request refund for previously printed IBI postage).

The second part of the article will briefly summarize the known IBI-IMI transitions carried out by the USPS (self-service kiosks), PC postage providers, and postage meter manufacturers. Except the current IMI kiosk postage from the USPS, all other types of known IMI postage show the acronym “IMI” in the human readable part of the indicium.

5. PES providers

5.1 USPS

Kiosk postage
Earlier this year (February 17, 2023), updates on self-service kiosks were implemented by the USPS. On that day, the USPS replaced the old Stamps.com PSDs (PSD IDs started with 06 2S) with new ones from Pitney Bowes (PSD IDs start with 02 6W). This change resulted in IMI indicia printed on the stamps of all three formats (Figures 2-4).

Figure 2
Figure 2. Strip format: IBI (top) and IMI (bottom) postage. Respective PSD IDs are shown enlarged in the insets on the right. While PSD IDs of IBI stamps start with 06 2S, the ones of IMI stamps start with 02 6W. This also applies to large-formatted kiosk stamps.

Figure 3
Figure 3. Small format - flag design: Forever IBI (left) and IMI (right) postage. Note the IMI code is wider (both symbols consist of 16 columns and 18 rows) than the IBI code (both symbols consist of 12 columns and 18 rows).

Figure 4
Figure 4. Large format: Top: IBI (left) and IMI (right) postage (image size reduced to 50%). Bottom: Respective indicia (IBI: left; IMI: right).

5.2 Stamps.com/Endicia

Stamps.com/Endicia has not implemented the new IMI standard as of October 2023.

5.3 Pitney Bowes

Online postage
Late 2021/early 2022, IMI indicia appeared on SendPro or PitneyShip online postage. Figure 5 depicts all four types of IMI-compatible First-Class SendPro stamps from sheets and coils.

Figure 5
Figure 5. Undated SendPro stamps with IMI code. Stamps from sheets: narrow (SendPro; top left) and wide format (PITNEY BOWES; top right). Stamps from coils: narrow (SendPro; bottom left) and wide format (PITNEY BOWES; bottom right).

Due to a software error, the “IMI” inscription was too small on narrow-formatted SendPro stamps (Figure 6). The font size was eventually corrected a few months later (Figure 6). A dated SendPro “envelope postage” indicium is shown in Figure 7. A postage indicium for an eBay standard envelope is shown in Figure 8. Various types of recent IMI online meter postage (shipping labels) are depicted in Figures 9 and 10.

Figure 6
Figure 6. IMI error on narrow-formatted SendPro stamps (small “IMI”; top) and corrected version (large “IMI”; bottom).

Figure 7
Figure 7. Dated SendPro “envelope postage” indicium and FIM (facing identification mark; on the left).

Figure 8
Figure 8. IMI-compatible 60¢ eBay standard envelope postage provided by Pitney Bowes.

Figure 9
Figure 9. Top portion of IMI-based First-Class shipping label from Pitney Bowes.

Figure 10
Figure 10. Top portions of IMI-based shipping labels from Pitney Bowes. The bottom one shows an Official Mail Commercial Plus Pricing (CPP) Priority stamp for a legal flat rate envelope.

Meter Postage
The USPS approved the extended use of various postage meter models manufactured by Pitney Bowes: SendPro® P-Series (P1000, P2000, and P3000) and Connect+® mailing systems (1000, 2000, 3000) will be withdrawn from service by December 31, 2027. Postage meters of the DM Infinity™ series can be used until June 30, 2026. As for all other IBI-compatible meters, they will be decertified on June 30, 2024, but can be used until June 30, 2026. Pitney Bowes’ latest postage meters all comply with IMI mailing requirements: SendPro® Mailstation, SendPro® C Lite, SendPro® C/+, SendPro® C Auto, and SendPro® MailCenter. Meter stamps with IMI are depicted in Figure 11. The first IMI compatible postage meters likely started operating in the fall of 2021.

Figure 11
Figure 11. Pitney Bowes meter stamps with IMI. The top left stamp was printed on November 15, 2021. This is the earliest known date for an IMI stamp the authors are aware of. The bottom left stamp shows an Official mail stamp.

5.4 EasyPost

So far, no reports regarding a switch to IMI online postage have surfaced.

5.5 DataPac

As of September 2023, all of the company’s postage meter models are not IMI-compatible.

5.5 Francotyp-Postalia (FP)

All of the company’s current PostBase mailing machines [PostBase mini, PostBase insight, PostBase vision, PostBase pro (DS), and PostBase ONE] are IMI-compatible. A representative IMI stamp from FP is shown in Figure 12. Similar to Quadient, the first IMI postage meters were introduced at the end of 2021.

Figure 12
Figure 12. FP meter stamps with IMI. The left stamp was printed on December 10, 2021, the earliest date known for an FP IMI meter stamp.

5.7 Quadient

Neopost, a company specialized in mailing equipment, was rebranded as Quadient on September 23, 2019. Therefore, current postage meter indicia exist with the impression Neopost or Quadient. Quadient’s iX-Series (iX-1, iX-3, and iX-5) postage meters are IMI compatible. IMI First-Class meter stamps from Neopost and Quadient are depicted in Figure 13, while Figure 14 shows, a rare 51¢ Quadient CORRECTION meter stamp. Quadient probably started the IBI to IMI transitioning at the end of 2021.

Figure 13
Figure 13. Neopost and Quadient meter stamps with IMI. The right stamp was printed on December 30, 2021, the earliest date known for a Quadient IMI meter stamp.

Figure 14
Figure 14. Quadient CORRECTION meter stamp with IMI.

Please send your comments about the article or any IMI-related information to the authors. Thank you.

The authors are indebted to Otto E. Bergman for help with the manuscript and Mark Metkin for providing images.